Systems and methods for skinning articles

ABSTRACT

A system for delivering and applying a flowable mixture to an article ( 311 - 313 ) is disclosed. The system includes a mixture delivery system ( 200 ) and a skinning system ( 300 ). The mixture delivery system ( 200 ) includes a mixer ( 220 ) configured to mix a dry material and a fluid to produce the flowable mixture, and a pump ( 235 ) configured to pump the flowable mixture to a delivery line. The skinning system ( 300 ) receives the flowable mixture from the mixture delivery system ( 200 ) through the delivery line. The skinning system ( 300 ) includes a skinning pipe ( 310 ) configured to apply the flowable mixture to the article ( 311 - 313 ) and a manifold ( 305 ) that supports the skinning pipe ( 310 ). The skinning system ( 300 ) also includes an article feeding mechanism ( 315 ) configured to push the article ( 311 - 313 ) into the skinning pipe ( 310 ). The skinning system ( 300 ) includes a transfer system ( 320 ) configured to hold the article ( 311 - 313 ) and move the article ( 311 - 313 ) out of the skinning pipe ( 310 ).

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of priority to U.S. ProvisionalPatent Application No. 61/891,147, filed Oct. 15, 2013, entitled“Process for Axial Skinning Apparatus,” and U.S. Provisional ApplicationNo. 62/063,364, filed Oct. 13, 2014, entitled “Systems and Methods forSkinning Articles.” This application also claims the benefit of priorityto and is a continuation-in-part of U.S. Nonprovisional application Ser.No. 14/083,722, filed Nov. 19, 2013, and U.S. Nonprovisional applicationSer. No. 14/217,848, filed Mar. 18, 2014. The contents of all of theabove-mentioned applications are incorporated herein by reference intheir entireties.

BACKGROUND

The present disclosure generally relates to skinning articles and, moreparticularly, to systems and methods for skinning articles.

SUMMARY

Exemplary embodiments of the present disclosure relate to a systemincluding an axial skinning system and a flowable mixture deliverysystem.

Further exemplary embodiments of the present disclosure relate to anaxial skinning system for skinning an article.

Further exemplary embodiments of the present disclosure relate to aflowable mixture delivery system for mixing and delivering a flowablemixture to a skinning system for applying to an article.

Further exemplary embodiments of the present disclosure relate tomethods for controlling a skinning process.

Further exemplary embodiments of the present disclosure relate tomethods for controlling a flowable mixture delivery process.

Further exemplary embodiments of the present disclosure relate tomethods for controlling a flowable mixture delivery process and askinning process to control the quality of skinned articles.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated herein and constitutepart of this specification, illustrate examples of the disclosed devicesand methods, and together with the general description given above andthe detailed description given below, serve to explain the features ofthe invention.

FIG. 1 is a schematic diagram of an exemplary of a system for skinningarticles.

FIG. 2 is a process flow diagram of an exemplary method for theoperation of the system for skinning articles.

FIG. 3 is a process flow diagram of an exemplary method for theoperation of the system for skinning articles.

FIG. 4 is a process flow diagram of an exemplary method for theoperation of the system for skinning articles.

FIG. 5 is a process flow diagram of an exemplary method for theoperation of the system for skinning articles.

FIG. 6 is a schematic diagram of an exemplary mixture delivery system.

FIG. 7 is a schematic diagram of an exemplary mixture delivery system.

FIGS. 8A-8B are schematic and perspective views of an exemplary mixerhead component.

FIG. 9 is a schematic diagram of an exemplary fluid dispensing system.

FIG. 10 is a schematic diagram of an exemplary fluid dispensing system.

FIG. 11 is a schematic diagram of a conventional fluid dispensingsystem.

FIG. 12 is a schematic diagram of a conventional fluid dispensingsystem.

FIG. 13 is a schematic diagram of an exemplary mixture storage device.

FIGS. 14A-14B are top and side views of schematic diagrams of theexemplary storage device.

FIG. 15 is a side view of a schematic diagram of the exemplary storagedevice.

FIGS. 16A-16B are schematic diagrams of an exemplary auger.

FIG. 17 is a schematic diagram of the exemplary of the auger.

FIG. 18 is a control diagram of an embodiment control system.

FIG. 19 is a graph of a particle size distribution of a dry material.

FIG. 20 is a graph of validation results of an exemplary feed forwardcontroller model.

FIG. 21 is a graph of validation results of an exemplary feed forwardcontroller model.

FIG. 22 is a control diagram of an exemplary adaptive feed forwardcontrol system.

FIGS. 23A-23B are graphs of density model validation results.

FIGS. 24A-24B are graphs of density model validation results.

FIG. 25 is a process flow diagram of an exemplary method of operating orcontrolling a mixture delivery system.

FIG. 26 is a perspective view of an exemplary skinning system.

FIGS. 27A-27E are schematic diagrams of an exemplary skinning process.

FIG. 28 is a schematic diagram of an exemplary vacuum system.

FIGS. 29A-29B are cross-sectional perspective views of the exemplaryvacuum system.

FIGS. 30A-30B are perspective views of exemplary vacuum chucks ofdifferent sizes.

FIGS. 31A-31B are perspective and top views of the exemplary vacuumsystem.

FIG. 32 is a perspective view of a portion of the exemplary skinningsystem.

FIG. 33 is a perspective view of a portion of the exemplary skinningsystem.

FIG. 34 is a perspective view of an exemplary manifold assembly.

FIG. 35 is a cross-section of the exemplary manifold assembly.

FIG. 36 is a perspective view of the exemplary manifold assembly withupper manifold piece removed.

FIG. 37 is a perspective view of an exemplary skinned article with a“ring” type defect.

FIG. 38 is a perspective view of the exemplary manifold assembly.

FIG. 39 is a perspective cross-section view of the exemplary manifoldassembly.

FIG. 40 is an underside perspective view of the exemplary manifoldassembly.

FIG. 41 is a perspective cut-away view of a portion of the exemplarymanifold assembly.

FIG. 42 is a graph of measured effect of an exemplary pressure reliefsystem.

FIG. 43 is cross-sectional view of the exemplary manifold assembly.

FIG. 44 is a perspective view of the exemplary manifold assembly.

FIG. 45 is a perspective view of the exemplary manifold assembly.

FIG. 46 is a perspective view of an exemplary skinning pipe with mountedskin thickness sensor.

FIGS. 47A-47B are top and cross-sectional views of the exemplary skinthickness sensor.

FIG. 48 is a schematic diagram of an exemplary skin thickness sensorbench test circuit.

FIG. 49 is a graph of measured voltages versus skin thicknesses.

FIG. 50 is a schematic diagram of an exemplary manifold assembly andcontrol system.

FIG. 51 is a graph of measured skin thickness output signals versus timefrom two skin thickness sensors.

FIG. 52 is a schematic diagram of an exemplary unskinned articledimension measuring device.

FIG. 53 is a graph of exemplary signals for measuring an unskinnedarticle dimension.

FIG. 54 is a perspective view of an exemplary article feeding mechanism.

FIG. 55 is a cross-section view of the exemplary article feedingmechanism.

FIGS. 56A-56B are perspective views of an exemplary article centeringmechanisms.

FIGS. 57A-57B are perspective views of the exemplary article centeringmechanisms.

FIGS. 58A-58B are schematic diagrams showing the function of anexemplary flexure shaft.

FIG. 59 is a cross-sectional perspective view of the output deflectionplot of a Finite Element Analysis where a force is applied to theexemplary flexure shaft.

FIG. 60 is an enlarged view of the exemplary flexure shaft.

FIG. 61 is a schematic diagram showing a simulation for the exemplaryarticle feeding mechanism.

FIG. 62 is a schematic diagram of a spacer positioned between twoarticles for the simulation.

FIG. 63 is a graph of maximum axial push forces as measure by forcesensors.

FIG. 64 is a perspective view of an exemplary article loading robot.

FIG. 65 is a perspective view of an exemplary article unloading robot.

FIG. 66 is a schematic diagram of an exemplary skinning system withforce sensors.

FIGS. 67A-67E are schematic diagrams of an exemplary skinning process.

FIG. 67F is a table displaying status of various components of theskinning system during the exemplary skinning process.

FIG. 68 is a schematic diagram of the exemplary skinning system withexemplary control systems.

FIG. 69 is a process flow diagram of an exemplary method for controllingthe skinning system.

FIG. 70 is a process flow diagram of an exemplary method for controllingthe skinning system.

FIG. 71 is a graph of an exemplary relationship between return pressureand article skinning speed.

FIG. 72 is a control diagram for an exemplary method for controlling theskinning system.

FIG. 73 is a control diagram for an exemplary method for controlling theskinning system.

FIG. 74 is a control diagram for an exemplary method for controlling theskinning system.

FIG. 75 is a graph of performance of exemplary skinning pipe pressurecontrol schemes.

FIG. 76 is a graph of an exemplary relationship between viscosity andreturn pressure set point.

FIG. 77 is a control diagram of an exemplary method for controlling theskinning pipe pressure based on a variation in the article dimension.

FIG. 78 is a control diagram of an exemplary method for controlling theskinning pipe pressure based on a variation in the article dimension.

FIG. 79 is a graph showing the impact of incoming article dimensionvariations on the skinning pipe pressure.

FIG. 80 is a graph showing the impact of incoming article dimensionvariations on the skinning pipe pressure.

FIG. 81 is a process flow diagram of an exemplary method for controllingthe skinning pipe pressure.

FIG. 82 is a graph of measured forces experienced by the upper and lowercarriage of the skinning system while articles are being skinned.

FIG. 83 is a graph of the measured forces while articles are beingskinned.

FIGS. 84A-84B are perspective views of skinned articles showing defectsand without defects.

FIG. 85 is a process flow diagram of an exemplary method for controllingthe skinning system.

FIG. 86 is a process flow diagram of an exemplary method for controllingthe mixture delivery system.

FIG. 87 is a process flow diagram of an exemplary method for controllingthe fluid dispensing system.

FIG. 88 is a process flow diagram of an exemplary method of operating orcontrolling the skinning system.

FIG. 89 is a process flow diagram of an exemplary method of operating orcontrolling the skinning system.

FIG. 90 is a process flow diagram of an exemplary method for operatingor controlling the skinning system.

FIG. 91 is a process flow diagram of an exemplary method for operatingor controlling the skinning system.

FIG. 92 is a process flow diagram of an exemplary method for detecting askin thickness.

FIG. 93 is a process flow diagram of an exemplary method for operatingor controlling the skinning system.

FIG. 94 is a process flow diagram of an exemplary method for operatingor controlling the skinning system.

DETAILED DESCRIPTION

The various examples will be described in detail with reference to theaccompanying drawings. Wherever possible, the same reference numberswill be used throughout the drawings and the descriptions to refer tothe same or like parts. References made to particular examples andimplementations are for illustrative purposes, and are not intended tolimit the scope of the invention or the claims. The examples shown inthe figures are not mutually exclusive. Features shown in one example(e.g., in one figure) may be included in other examples (e.g., in otherfigures).

The disclosed article, and the disclosed system and method of making(e.g., skinning) the article provide one or more advantageous featuresor aspects, including for example as discussed below. Features oraspects recited in any of the claims are generally applicable to allfacets of the disclosure. Any recited single or multiple feature oraspect in any one claim can be combined or permuted with any otherrecited feature or aspect in any other claim or claims.

After-treatment of exhaust gas from internal combustion engines may usecatalysts supported on high-surface area substrates and, in the case ofdiesel engines and some gasoline direct injection engines, a catalyzedfilter for the removal of carbon soot particles. Filters and catalystsupports in these applications may be refractory, thermal shockresistant, stable under a range of pO2 conditions, non-reactive with thecatalyst system, and offer low resistance to exhaust gas flow. Porousceramic flowthrough honeycomb substrates and wall-flow honeycomb filters(generically referred to herein as honeycomb bodies) may be used inthese applications.

Particulate filters and substrates may be difficult to manufacture toexternal dimensional requirements set by original equipmentmanufacturers (OEMs) and the supply chain due to drying and firingshrinkage during manufacturing. Consequently, ceramic cement may be usedto form an exterior skin of a honeycomb body, which has been machined or“contoured” to a desired dimension. As used herein, the term “honeycombbody” includes single honeycomb monoliths and honeycomb bodies formed bymultiple honeycomb segments that are secured together, such as by usinga ceramic cement to form a monolith. Ceramic cement may be mixed andapplied to a fired, contoured or segmented honeycomb body and the wetskin allowed to dry. The act or process of applying ceramic cement tothe exterior of the honeycomb body is referred to herein as “skinning”the honeycomb body. A honeycomb body having skin disposed thereon isreferred to herein as a “skinned” honeycomb body. Examples of systemsand methods for skinning articles are disclosed in InternationalApplication Nos. PCT/US2012/066713, filed Nov. 28, 2012, andPCT/US14/38901, filed May 21, 2014, the contents of the aboveapplications are incorporated herein by reference in their entireties.

Once the wet skin on the honeycomb body has dried an inspection of theskin can be conducted requiring labor, cost, and time. When a defect isfound, it may be too late to correct a skinning process that caused thedefect in sequential parts skinned in the same production run. Thedefects may be corrected requiring additional labor, time, and cost, orthe production run may have to be scrapped if the defects are notrepairable causing lost production and manufacturing inefficiencies.

The skinning process described above may be applied to any article, bywhich a coating, such as a glass, cement, ceramic, or polymer, isapplied to an outer surface of the article, as a step in themanufacturing process. Current methods and systems for skinning articlesare process-intensive operations that increase the manufacturing costsof finished products.

The various embodiments include a manufacturing system for efficientlyskinning articles of manufacturing conducive to continuous manufacturingby implementing feed-forward and feed-back control processes to ensuresubstantially consistent product quality. Embodiments also include thevarious subsystems and components that are configured to enable theoverall manufacturing system to operate with efficiency and qualitycontrols.

The hardware used to implement the various illustrative logics, logicalblocks, modules, and circuits described in connection with the aspectsdisclosed herein may be implemented or performed with a general purposeprocessor, a programmable logic controller (PLC), digital signalprocessor (DSP), an application specific integrated circuit (ASIC), afield programmable gate array (FPGA) or other programmable logic device,discrete gate or transistor logic, discrete hardware components, or anycombination thereof designed to perform the functions described herein.A general-purpose processor may be a microprocessor, but, in thealternative, the processor may be any conventional processor,controller, microcontroller, or state machine. A processor may also beimplemented as a combination of computing devices, e.g., a combinationof a DSP and a microprocessor, a plurality of microprocessors, one ormore microprocessors in conjunction with a DSP core, or any other suchconfiguration. Alternatively, some operations or methods may beperformed by circuitry that is specific to a given function.

When an element or layer is referred to as being “on,” “connected to,”or “adjacent” another element or layer, it can be directly on, directlyconnected to, or directly adjacent to the other element or layer, orintervening elements or layers may be present. In contrast, when anelement or layer is referred to as being “directly on,” “directlyconnected to,” or “directly adjacent” another element or layer, thereare no intervening elements or layers present. The phrase “at least oneof X, Y, or Z” can be construed as X only, Y only, Z only, or anycombination of two or more items X, Y, and Z (e.g., XYZ, XYY, YZ, ZZ).

While terms such as, top, bottom, side, upper, lower, vertical, andhorizontal are used, the disclosure is not so limited to these exemplaryembodiments. Instead, spatially relative terms, such as “top,” “bottom,”“horizontal,” “vertical,” “side,” “beneath,” “below,” “lower,” “above,”“upper” and the like, may be used herein for ease of description todescribe a relationship between one element or feature and anotherelement(s) or feature(s) as illustrated in the figures. The spatiallyrelative terms are intended to encompass different orientations of thedevice in use or operation in addition to the orientation depicted inthe figures. For example, if the device in the figures is turned over,elements described as “below” or “beneath” other elements or featureswould then be oriented “above” the other elements or features. Thus, theexemplary term “below” can encompass both an orientation of above andbelow. The device may be otherwise oriented (rotated 90 degrees or atother orientations) and the spatially relative descriptors used hereininterpreted accordingly.

The terms “include,” “includes,” or the like means encompassing but notlimited to, that is, inclusive and not exclusive.

The term “about” modifying, for example, the quantity of an ingredientin a composition, concentrations, volumes, process temperature, processtime, yields, flow rates, pressures, viscosities, and like values, andranges thereof, employed in describing the embodiments of thedisclosure, refers to variation in the numerical quantity that canoccur, for example: through typical measuring and handling proceduresused for preparing materials, compositions, composites, concentrates, oruse formulations; through inadvertent error in these procedures; throughdifferences in the manufacture, source, or purity of starting materialsor ingredients used to carry out the methods; and like considerations.The term “about” also encompasses amounts that differ due to aging of acomposition or formulation with a particular initial concentration ormixture, and amounts that differ due to mixing or processing acomposition or formulation with a particular initial concentration ormixture.

The indefinite article “a” or “an” and its corresponding definitearticle “the” as used herein means at least one, or one or more, unlessspecified otherwise.

Abbreviations, which are well known to one of ordinary skill in the art,may be used (e.g., “h” or “hr” for hour or hours, “g” or “gm” forgram(s), “mL” for milliliters, and “RT” for room temperature, “nm” fornanometers, “rpm” for round per minute, “lb” for pound, and likeabbreviations).

Specific values disclosed for components, ingredients, additives, times,temperatures, pressures, and like aspects, and ranges thereof, are forillustration only; they do not exclude other defined values or othervalues within defined ranges. The apparatus, and methods of thedisclosure can include any value or any combination of the values,specific values, and more specific values described herein.

The term “skinning an article” or “skin an article” means applying orcoating (or apply or coat), under a pressure, a flowable mixture, suchas cement, to an article, such as an outer (e.g., exterior, lateral)surface of a ceramic article, e.g., a ceramic honeycomb substrate. Theterm “skin,” “skin material,” or “skinning material” refers to theflowable mixture that is applied under a pressure to the article. Thus,an unskinned (or bare) article is an article prior to being skinned(e.g., coated with the flowable mixture), and a skinned article is anarticle that has been skinned (e.g., coated with the flowable mixture).

The term “mixture” may also be referred to herein as a “batch.” Amixture is obtained by mixing one material, such as a dry material, withanother material, such as a fluid. The term “mixture delivery system”may also be referred to as a “batch delivery system.” The term “fluid”may include liquid, gas, steam, or any combination thereof.

The term “axial skinning” as used herein refers to applying or coating aflowable mixture to an outer surface of an article in an axial orlongitudinal direction. In some embodiments, axial skinning may beachieved by using a pipe. In such embodiments, a flowable mixture isapplied to the outer surface of the article by the pipe as the articlemoves or travels within an inner space of the pipe along the axialdirection of the pipe.

The term “article” as used herein refers to a part or a body having athree-dimensional shape. The shape may be any suitable shape, such as,for example, a cylinder shape, a cubic shape, a prism shape, anasymmetric three-dimensional shape, etc. The article may be any part orbody to which a skin may be coated. In some embodiments, the article maybe a porous part such as, for example, a porous honeycomb substrate fora filter. In some embodiments, the filter may be a particulate filterthat may be used in various industries, such as, for example, ingasoline and/or diesel, high duty and/or heavy duty vehicles for aftertreatment emission control. The substrate may include any suitablestructure, form, and/or shape. For example, the substrate may include aporous ceramic honeycomb structure having a plurality of intersectingwalls forming mutually adjoining cell channels for air flows. The crosssection of the substrate may have any suitable shape, such as a circle,a square, a rectangle, a triangle, an asymmetric shape (e.g., a shapewith two axes having different axial length). An asymmetric shape forthe cross section may include any shape that is non-symmetric. Forexample, an asymmetric shape may include two axes having differentlengths or diameters.

The term “flowable mixture” refers to any mixture of a fluid and a drymaterial that has suitable properties for application to an article. Oneexample of the flowable mixture is cement, such as a cement composition,which can flow (e.g., under pump pressure) before it settles. The cementmay include any cement with a suitable composition, such as, forexample, a glass powder filler, a binder, and a solvent. The glasspowder filler may include at least one of a fused silica (SiO₂), groundcordierite, grog, silica soot, mullite, or other refractory compounds.Once the flowable mixture is applied to the outer surface of thearticle, the flowable mixture becomes attached or affixed to, disposedon, or otherwise a part of the article (e.g., referred to as the skin ofthe article).

The skinned articles may include defects. The term “defect” may includeany of a fast flow defect, a starvation defect, a pock defect, a pitdefect, and a ring defect. The term fast flow defect refers to a bulgingout of the skin from the skinned outer surface of the article, which mayoccur when excessive localized pressure or reduced viscosity hasproduced extra flowable mixture. A starvation defect refers to a lack ofskin (e.g., flowable mixture) on a portion of the outer surface of thearticle. A pock defect refers to a small depression (e.g., a craterdefect) in the skin surface. A pit defect refers to a pock thatpenetrates the thickness of the skin from the skin surface to the outersurface of the article beneath the skin, including a defect that leavesa portion of the article uncovered. A ring defect refers to a ring ofextra flowable mixture on the skin.

The term “skinning speed” used herein refers to the speed of applyingthe flowable mixture to the article (or skinning the article). Theskinning speed indicates how fast the articles are skinned. The skinningspeed also relates to how fast the articles travel or move through thepipe. The unit for the skinning speed may be millimeter per second(mm/sec).

The term “skinning pipe” refers to a pipe included in the skinningsystem that receives an article and applies (e.g., coats or skins) theflowable mixture to the article as the article moves through an innerspace of the pipe. The skinning pipe may also be referred tointerchangeably herein as a pipe, a unipipe, a chamber, or a skinningchamber. The skinning pipe may include a circumferential wall defining abore (e.g., an inner space). The skinning pipe may include any suitableshape for the cross section, such as circle, rectangle, square,triangle, polygon, asymmetric shape, etc. The shape of the cross sectionof the skinning pipe may substantially match that of the article to beskinned. The dimension (e.g., diameter, radius, circumference, axiallength, and/or outer peripheral length) of the inner space defined bythe circumferential wall of the skinning pipe may be slightly greaterthan that of the article.

The term “pressure of the skinning pipe” refers to a pressure measuredat the skinning pipe. The pressure of the pipe may also be referred toas a skinning pipe pressure, a unipipe pressure, or a pressure of theunipipe. The skinning pipe pressure may be measured at an inlet of theskinning pipe that receives the flowable mixture and/or at another placeadjacent the portion of the skinning pipe where flowable mixture isapplied to the article (e.g., at an outlet of a manifold that deliversthe flowable mixture to the skinning pipe).

The term “parameter” includes any system operating parameter. Aparameter may be a parameter associated with a set point or a targetvalue. A parameter may be a parameter associated with a changing value(e.g., a parameter that is continuously, periodically, or intermittentlyadjusted b a controller, which may also be referred to as “controlactuator”). A parameter may be a parameter that is measured by ameasuring device (e.g., a measured parameter).

The term “pressure relief system” may also be referred to as “pressureboost system” or “pressure adjustment system.” These terms referinterchangeably to a system that changes the pressure of a device or aportion of the overall manufacturing system, such as, for example, theskinning pipe.

The term “screwfill ratio” used herein refers to a ratio of the feedrate over the mixer speed. Its unit may be, for example, lb/hour/rpm,wherein rpm refers to round per minute.

A “position” of a flow control valve, such as a valve for controllingfluid flow or flow of the flowable mixture, refers to the amount ofopening of the valve, which determines the amount of the flow.

A “position” of a pressure relief system (which may also be referred toas a pressure release system, or a pressure boost system), which mayinclude an actuator to move another element, refers to the amount ofactuation the actuator provides, which in turn determines the amount ofmovement the actuator may cause to the other element. Alternatively, theterm “position” may refer to the amount of movement the actuator causesto the other element. For example, the pressure relief system may usethe actuator to move a ring up and down along a skinning pipe. The term“pressure relief system position” or “pressure boost system position”refers to the amount of actuation the actuator provides, or theresulting amount of movement of the ring.

Overview of Systems and Controls

The system for skinning articles may include a mixture delivery system,a skinning system, and a control system. The mixture delivery system maybe configured to produce a flowable mixture and deliver the flowablemixture to the skinning system. The skinning system may be configured toapply (e.g., coat) the flowable mixture to the articles. The controlsystem may be configured to control at least one parameter (e.g.,various operational or control parameters) associated with the mixturedelivery system and/or the skinning system. For example, the controlsystem may be configured to receive measurement data from varioussensors in the mixture delivery system and skinning system, and issuecommands generated via feed-forward and feed-back algorithms to controla number of process parameters, non-limiting examples of which includethe density, viscosity, and flow rate of the flowable mixture, theskinning speed, the skinning pipe pressure, etc., in order to controlthe quality of the skin.

In some embodiments, the skinning process may be a continuous process.For example, the skinning process may be a highly automated process thatuses robots to feed unskinned articles into the skinning system, and toremove skinned articles from the skinning system. In some embodiments,the mixture delivery system may also be a continuous mixing anddelivering system. The continuous style mixer may continuously mix andproduce the flowable mixture. A pump may continuously pump the flowablemixture to a delivery line leading to the skinning system. Thecontinuous mixing and delivering process provides a continuous flow ofthe flowable mixture that has substantially consistent density and/orviscosity. The continuous mixing and delivering process prevents theflowable mixture from settling or drying up. In some embodiments, theflowable mixture may be highly viscous and abrasive (e.g., the flowablemixture may be highly viscous cement). The highly viscous flowablemixture may be continuously produced and pumped to the delivery lineleading to the skinning system at a low flow rate. Although thedisclosed system enables continuous skinning of the articles, system 100may also be used for index push skinning process, which isnon-continuous.

In various embodiments some subsystems and components of the mixturedelivery system and the skinning system may operate in a batch-likemanner while supporting a continuous skinning operation. For example,the mixer may operate as needed to produce batches sufficient to supporta continuous feed to the skinning system via the mixture delivery pump.As another example, the skinning system may pause the application of theskinning mixture between articles if there is a gap or pause betweenarticles passing through the system, such as in an index push skinningprocess. Therefore, references to system and subsystems operating“continuously” include batch operations that support continuous ornear-continuous processing of articles passing through the skinningsystem.

The system for skinning articles may include various sensing ormeasuring devices, sensors, meters and the like (collectively “measuringdevices”) configured to monitor, measure, or detect system parameters,such as force, pressure, density, viscosity, flow meters, defects inskinned articles, skin thickness in the skinned articles, dimensions(e.g., diameter, radius, circumference, axial length, and/or outerperipheral length) of unskinned articles and/or skinned articles, etc.The control system may implement feedback controls, feed forwardcontrols, or a combination of both feedback and feed forward controls tocontrol various parameters to enable the system to achieve asubstantially consistent level of quality control. For example, thecontrol system may employ a feed forward augmented feedback controlprocess to control the mixture delivery system and/or the skinningsystem based on the measured system parameters. In some embodiments,real-time measurements of the system parameters may be provided to thecontrol system as disturbance, inputs, or feedback. The control systemis configured to control system parameters so that the final skinnedproduct achieves a desired level of quality, such as defect free orsubstantially defect free (e.g., nearly defect free).

Mixture Delivery System

In some embodiments, the mixture delivery system may be an automated orsemi-automated system. Dry materials may be weighed and blended in anautomated blender, and fed into a continuous loss-in-weight feeder, sothat the blended materials flow into the continuous style mixer. Themixer may be fed continuously by multiple loss-in-weight feeders ofindividual dry materials, or by fewer feeders using pre-blendedcomponents of all dry materials. The mixer may be fed continuously byone or more liquid dispensing systems that control flow rates of fluidscontinuously. The one or more liquid dispensing systems may include oneor more peristaltic pumps, one or more gear pumps, one or more liquidloss-in-weight feeders, or one or more flow meters. Fluids, such asliquids, may be injected into the mixer at target proportions and mixedwith the dry materials within the mixer. By controlling at least one ofa dry material feed rate, mixer speed, and a backup length of the mixer,the mixer may produce the flowable mixture (e.g., cement) with thenecessary properties (e.g., density, viscosity) to produce the desiredproduct and with the consistency necessary to achieve quality controlrequirements.

The flowable mixture may be temporarily stored in a storage device orvessel, such as, for example, a hopper, which may be configured andsized to support delivery of a continuous stream of the mixture to theskinning system. The storage device may include an auger that drives theflowable mixture to a downstream pump. The auger may be configured suchthat it is disposed in close proximity to the inner wall of the storagedevice, thereby effectively preventing introducing air bubbles into theflowable mixture when the auger drives the flowable mixture into thepump.

In some embodiments, the mixture delivery system may include a pump, adelivery line including a delivery valve (which may be an assembly ofvalves), and a recirculation line with one end connecting the deliveryline downstream of the delivery valve, and the other end connecting thestorage device. The pump may be configured to advance the flowablemixture through the delivery line leading to the skinning system.

The recirculation line may be configured to return all or a portion ofthe flowable mixture from the delivery line back to the storage devicedepending upon an operating state of the system. For example, prior tothe start of the skinning process, the delivery valve(s) may bepositioned in a manner that prevents the flowable mixture from flowingto the skinning system and directs all of the flowable mixture pumpedinto the delivery line to return back to the storage device via therecirculation line. In this configuration, which may be useful to ensurethe mixture meets desired properties of concentration, viscosity,density and pressure before it is introduced to the skinning system, theflowable mixture may be recirculated in a loop from the storage device,through the pump, delivery valve, and the recirculation line and backinto the storage device.

The recirculation of the flowable mixture within the recirculation linemay continue until a return pressure within the recirculation linereaches a predetermined threshold return pressure and/or other mixtureproperties or consistency are achieved. When the return pressure reachesthe threshold return pressure and/or when the mixture properties reachthe threshold properties, the skinning system may be started and thedelivery valve(s) may be positioned to allow the flowable mixture toflow to the skinning system. During the skinning process, therecirculation line may continue to recirculate a portion of the flowablemixture between the delivery line, the storage device, and the pump,such as to control the pressure within the mixture. For example, flowthrough the recirculation line may be maintained as long as the returnpressure is greater than the threshold return pressure. Recirculating aportion of the flowable mixture from the delivery line back to thestorage device may help to ensure the consistency of the properties ofthe flowable mixture.

In some embodiments, the skinning system may need to be paused orstopped for a short period of time (e.g., 1-3 hours) for services orrepairs (e.g., cleaning or changing a component). When the skinningsystem is paused or stopped for a short period of time (e.g., 1-3hours), the mixture delivery system may continue to run, such that theflowable mixture produced is continuously recirculated to preventsettling and to ensure consistency in the mixture properties. After theskinning system is restarted, the mixture delivery system may continueto deliver the flowable mixture to the skinning system.

In some embodiments, the mixture delivery system may include an optionalpurge line in addition to or instead of the recirculation line. Thepurge line may be connected to the delivery line at one end and to adumpster, tote, or material recovery system at another end. When thepurge line is opened (e.g., when a valve in the purge line is opened),the flowable mixture may be directed into the purge line, therebypurging or dumping the flowable mixture from the delivery line. Forexample, when the properties of the flowable mixture do not meet therequirements for the skinning system, the purge line may be used to dumpthe flowable mixture, thereby preventing the undesired flowable mixturefrom flowing to the skinning system. In some embodiments, prior tostarting the skinning process, the purge line may be opened to dump aninitial amount of flowable mixture so that no flowable mixture isdirected to the skinning system, until a certain pressure has built upin the delivery line and/or the properties (e.g., density and/orviscosity) of the flowable mixture have met the requirements.

In some embodiments, the mixture delivery system may include a fluiddispensing system configured to dispense a fluid, such as a liquid, tothe mixer. The fluid dispensing system may include a storage tankconfigured to store a fluid, a pump configured to pump the fluid, arecirculation loop with one end connected to an outlet of the pump, andthe other end connected to an inlet of the storage tank, and at leastone distribution branch connected to the recirculation loop. Therecirculation loop may be configured to continuously recirculate thefluid between the storage tank and the pump, which may prevent settlingof the fluid, e.g., when the fluid is not being injected into the mixer.The recirculation loop may provide a steady flow and a substantiallyconstant back pressure for the at least one distribution branch.

The fluid dispensing system may include a number of distributionbranches, with each distribution branch including flow meters and flowcontrol valves, allowing each distribution branch to be controlledindependently to dispense the fluid into the mixer without the need ofcoordinating sequences. The recirculation loop may include aproportional flow control valve, whose valve position may be adjusted bythe control system based on at least one of a speed of the pump, a pumppressure, or a pressure in the recirculation loop downstream the pump.The control system may control the proportional flow control valve suchthat a substantially constant back pressure is maintained in therecirculation loop to which the distribution branches are connected. Thefluid dispensing system may be scalable. For example, when multiplemixers are included in the system, more distribution branches may beadded to the recirculation loop with limited or no impact on theexisting distribution branches thanks to the steady flow andsubstantially constant back pressure in the recirculation loop.

The mixture delivery system may include a mixture control system thatperforms a mixture control process for controlling the rheology of theflowable mixture, such as the density and viscosity. In someembodiments, the mixture control system may be a control system that isseparate from but responsive to the overall control system (i.e.,control system 400 described below with reference to FIG. 1). In otherembodiments, control of the mixture delivery system may be includedwithin the control processes of the overall control system, such aswithin a mixture delivery control system module. The mixture controlsystem may predict the shift in the rheology based on variations inmeasured properties of the raw materials, such as variations in measuredparticle size distribution (“PSD”) of the dry material.

The mixture control system may include a feed forward controller thatpredicts (estimates, calculates, or determines) the effect of avariation in the particle size distribution of the dry material onrheology of the flowable mixture. For example, the feed forwardcontroller may determine an adjustment to the amount of fluid to beadded to the mixer (e.g., an amount of the water or a “water call”) tomaintain the rheology of the flowable mixture within desired tolerances.For example, the feed forward controller may determine the adjustment inthe water call based on the variation in the properties of the rawmaterials (e.g., measured particle size distribution), and the mixturecontrol system may send a signal to the mixer and/or the fluiddispensing system to adjust the water or another fluid added to themixer based on the adjustment to the water call.

The mixture control system may also include at least one feedbackcontroller that uses real-time or near real-time measurements of thedensity and/or viscosity of the flowable mixture for skinning todetermine adjustments to the water call of the mixer and/or the speed ofthe mixer (or the screwfill ratio of the mixer) necessary to ensure thatthe density and/or viscosity remain within the desired density and/orviscosity process limits or requirements.

With the combined feed forward water call adjustment using the PSDmeasurements and the feedback control of the density and viscosity, themixture delivery system may provide a continuous flow of the flowablemixture with substantially consistent mixture (or batch) rheology, whichaids in ensuring a high quality (i.e., defect free or substantiallydefect free) skinned product.

The mixture delivery system of the various embodiments may, according tovarious embodiments described herein, reduce costs and labor, improvethe material utilization rate, reduce waste of the raw materials, reducethe line pressure, and/or reduce the complexity of the system. Themixture delivery system also enables in-line measure and control of therheology of the flowable mixture.

Skinning System

The skinning system may include an upper axis including a manifoldmounted with a skinning pipe through which articles are inserted toreceive the flowable mixture on the outer surfaces of the articles. Theskinning system may also include an upper carriage mounted with atransfer system. In some embodiments, the transfer system may include avacuum system. For discussion purposes, a vacuum system is used as anexample of the transfer system. The transfer system may include anyother suitable mechanisms for transferring skinned articles or at leastpartially skinned articles without introducing defects to the skins. Forexample, the transfer system may include a plurality of pins ormechanical fingers that may be inserted into the body of the skinnedarticles from the top surface. The pins or mechanical fingers may gripthe internal structure of the skinned articles (e.g., the internal wallsof a honeycomb article) such that the transfer system may pull thearticle out of the skinning pipe.

In some embodiments, the upper carriage and the vacuum system may belocated above the skinning pipe in a vertical direction, and may move upand down along a vertical rail mounted on a skinning system supportframe. The skinning system may also include a lower carriage supportingan article feeding mechanism. The lower carriage and the article feedingmechanism may be located below the skinning pipe in the verticaldirection. Thus, the skinning system may utilize a vertical axialskinning process, in which the unskinned article is pushed into theskinning pipe by the article feeding mechanism from below the skinningpipe, such that the article travels or moves upwardly in the verticaldirection along the inner space of the skinning pipe.

As the article moves along the inner space of the skinning pipe, theskinning pipe may apply (e.g., coat), under a pressure, the flowablemixture to an outer surface of the article through a plurality ofapplication holes located on a circumferential wall of the skinningpipe. The flowable mixture may flow from grooves or channels locatedinside the manifold to the application holes on the circumferentialwall. The flowable mixture within the grooves or channels of themanifold may be pressurized such that it flows from the grooves orchannels to the circumferential wall of the skinning pipe under apressure.

The article feeding mechanism located below the skinning pipe may feedthe unskinned articles to the skinning pipe by pushing one or morearticles through the skinning pipe. The vacuum system located above theskinning pipe may be configured to generate one or more vacuum zones(e.g., multiple vacuum zones). The vacuum system may be referred to as amulti-zone vacuum system. The vacuum system may be configured to hold anat least partially skinned article and pull (e.g., move or lift) itupwardly out of the skinning pipe as the articles move along the innerspace of the skinning pipe. When multiple vacuum zones are used togetherwith different spacers inserted between multiple articles, the vacuumsystem may hold and pull up multiple articles simultaneously.

The skinning system may include at least one force sensor configured tomeasure at least one force experienced by the upper carriage and/or thelower carriage. The measured force may be used by a skinning controlsystem to determine the timing of the “hand-off” between the articlefeeding mechanism and the vacuum system (e.g., when the article feedingmechanism should push the articles. For example, the skinning system mayuse measured forces to determine when to stop pushing the articlesthrough the pipe, the position of the article feeding mechanism (or alower carriage to which the article feeding mechanism is mounted),and/or the speed of the pushing. The skinning system may also use themeasured forces to determine when to activate or deactivate one or morevacuum zones generated by the vacuum system within the article, when thevacuum system should pull the articles, position of the vacuum system(or an upper carriage to which the vacuum system is mounted), and/or thespeed of the pulling.

The skinning control system may be configured to perform a skinningcontrol process for controlling the operations of the skinning system.In some embodiments the skinning control system may be a control systemthat is separate from but responsive to the overall control system(i.e., control system 400 described below with reference to FIG. 1). Inother embodiments, control of the skinning system may be included withinthe control processes of the overall control system, such as within askinning control system module. In some embodiments, the skinningcontrol system and the mixture control system may form portions of theoverall control system 400. Any processes described in this disclosureas being performed by the skinning control system or the mixture controlsystem may also be performed by the overall control system 400. Inaddition, any processes described in this disclosure as being performedby one control system (e.g., the skinning control system) may also beperformed by other control systems (e.g., the mixture control system).

The article feeding mechanism may include a flexure shaft configured tocompensate for misalignment between an unskinned article and the innerspace of the skinning pipe. The flexure shaft may be configured to bendor deflect within a predetermined degree of flexure in order to corrector compensate for misalignment of articles in the skinning pipe, whichmay be caused by, e.g., parallelism errors in the surfaces of thearticles. The flexure shaft may function to enable misaligned unskinnedarticle to be pushed into the skinning pipe without jamming. The articlefeeding mechanism may include a centering mechanism configured to centeror align each article with the inner space of the skinning pipe, beforeand/or when the unskinned article is pushed into the skinning pipe.

The skinning system may include at least one laser device (e.g., atleast one first laser device) located adjacent an inlet of the skinningpipe that are configured to measure a dimension (e.g., diameter, radius,circumference, axial length, and/or outer peripheral length) of eachunskinned article. For example, the laser device located adjacent theinlet of the skinning pipe may be configured to measure the diameters ofunskinned articles. In some embodiments, two or more laser devices maybe disposed at the inlet to measure the diameters of the unskinnedarticles. Instead of measuring the diameters of the articles, thecircumference, axial length, or the outer peripheral length may bemeasured. Controls based on the diameter measurement may be modified ascontrols based on measurements of the radius, the circumference, axiallength, or the outer peripheral length. The circumference refers to theouter peripheral length of a cylindrical article, which may have acircular cross section. The outer peripheral length refers to thelateral length of the outer surface of the article having any suitableshape for its cross section, such as a circular shape, a rectangularshape, a square shape, an oval shape, a triangular shape, a polygonshape, or an asymmetric shape. Measured dimension from the dimensionmeasuring laser devices may be used by the control system to adjustvarious system parameters, such as the skinning speed (e.g., the speedof the article through the skinning pipe) and/or the position of apressure adjustment system, in order to produce a skin thickness withinproduct tolerances (i.e., to compensate for variability in articledimension).

The skinning system may also include a plurality of laser deviceslocated adjacent an outlet of the skinning pipe that are configured tomonitor and/or detect the presence of defects in the skin of eachskinned article (hereinafter the laser devices configured to monitorand/or detect defects may be referred to as defect monitoring laserdevices). The defect monitoring laser devices may monitor the presenceof a defect on the skin of a skinned or at least partially skinnedarticle. Once a defect is detected, the defect monitoring laser devicesmay detect or determine a type of the defect (e.g., a fast flow type, astarvation type, a pit type, a pock type, a ring type, etc.) Data fromthe defect monitoring laser devices may be used by the control system toadjust various system parameters that affect skin defects (e.g.,pits/pocks, fast flow, and starvation), such as the speed of the pump,which may affect the pressure within the flowable mixture (which in turnmay affect the fast flow and/or starvation types of defects), and/or thespeed of the mixer, which may affect the density of the flowable mixture(which in turn may affect the pit/pock types of the defect).

The manifold for delivering the flowable mixture to the skinning pipemay include various locating pads and/or locating blocks that enablefast assembly and/or disassembly. With these locating devices, after themanifold is disassembled for services, repairs, or change of a differentmanifold, the manifold may be re-assembled to the skinning system withprecision, such that the skinning pipe remain aligned with othercomponents of the skinning system. The manifold may include a pressurerelief system configured to adjust a space adjacent the skinning pipeavailable for the flowable mixture to flow, thereby adjusting thepressure of the flowable mixture within the skinning pipe. The manifoldmay also include a skin thickness sensor configured to measure athickness of the skin applied to the skinned article.

The skinning system may include a skinning control system. The skinningcontrol system may control the skinning process using feed forwardcontrols, feedback controls, or a combination thereof. In someembodiments, the skinning control system may implement a feed forwardaugmented feedback control that uses real-time or near real-timefeedback from the skinning process (e.g., real-time or near real-timemonitoring and/or detection of the defects, the pressure of the skinningpipe, and other parameters associated with the mixture delivery system)to control the quality of the final skinned article (e.g. to managepits/pocks, fast flow, and/or starvation). In some embodiments, theskinning control system may be a control system that is separate frombut responsive to the overall control system (i.e., control system 400described below with reference to FIG. 1). In other embodiments, controlof the skinning system may be included within the control processes ofthe overall control system, such as within a skinning control systemmodule.

Control System

The control system may be configured to monitor the various measuringdevices within the system (including the measuring devices describedabove) and issue control signals to various valves, pumps, and actuators(including the controls described above) in order adjust systemparameters to ensure the skinning process meets quality and consistencyrequirements. As mentioned above, the control system may be a singleintegrated control system (e.g., control system 400 in FIG. 1), or acombination of a mixture delivery control system, a skinning controlsystem, and/or a supervisor control system (i.e., a distributed controlsystem). The difference between an integrated control system and adistributed control system is a matter of design preference, and theoperations of either configuration of control system are substantiallythe same. Therefore, descriptions of the control system(s) of thevarious embodiments refer simply to the “control system” withoutintending to limit the embodiments or the claims to a particular controlsystem architecture.

The control system may not start the skinning process until a returnpressure within a recirculation line of the mixture delivery system, ora delivery pressure within the delivery line has reached a predeterminedthreshold value. In some embodiments, the skinning control system mayimplement a start-up control scheme to reduce the transient time duringthe start up of a continuous axial skinning process. The start-upcontrol scheme may include adjusting a pressure relief system to changethe space adjacent the skinning pipe available for the flowable mixtureprior to the start of the skinning process. The pressure relief systemmay be adjusted based on the target skinning speed. In some embodiments,the start-up control scheme may include incrementally increasing, e.g.,in multiple operations or stages, the skinning speed after the start ofthe skinning process until it reaches the desired skinning speed, ratherthan increasing the skinning speed in one operation or stage from zeroto the target skinning speed.

The control system may include a multiple-layered feedback control loopsto enable delivery of defect-free skinned articles. In some embodiments,the control system may include a first feedback control loop to controlthe return pressure within the recirculation line, and a second feedbackcontrol loop to control the skinning pipe pressure based on the controlof the return pressure. In some embodiments, the control system mayinclude a feedback control loop to control the skinning pipe pressure bydirectly controlling the pump speed or delivery valve position. In someembodiments, the control system may include a first feedback controlloop to control a flow rate of the flowable mixture, and a secondfeedback control loop to control the skinning pipe pressure based on thecontrol of the flow rate.

The control system may proactively compensate for changes in theskinning pipe pressure due to variations in the properties of theflowable mixture. In some embodiments, the control system may include afeed forward controller configured to predict (estimate, calculate, ordetermine) the impact of the variation in the properties of the flowablemixture, such as the viscosity and/or flow rate). An output of the feedforward controller may be fed into the feedback control loop forcontrolling the skinning pipe pressure.

The control system may also proactively compensate for changes in theskinning pipe pressure due to variations in the dimensions (e.g.,diameter, radius, circumference, axial length, and/or outer peripherallength) of the incoming unskinned articles. The dimension measurementsfrom the laser devices located adjacent the inlet of the skinning pipemay be input into a feed forward controller, which may predict(estimate, calculate, or determine) the impact of the variation of thedimensions of the incoming unskinned articles on the skinning speedand/or the pressure relief system. An output of the feed forwardcontroller may be fed into a feedback loop for controlling the skinningpipe pressure.

In some embodiments, the skinning system may monitor the presence of adefect in a skinned article and/or detect a type of a defect in askinned article, e.g., using the defect monitoring laser devices locatedadjacent the outlet of the skinning pipe described above. The controlsystem may implement a feedback control loop to automatically adjust setpoints (e.g., target values) for system parameters (e.g., skinning pipepressure set point) based on the type of defect detected.

Overall System and Controls

FIG. 1 is an exemplary system 100 for skinning articles. The system 100may include a mixture delivery system 200, a skinning system 300, and acontrol system 400. Although various components, modules, units, devicesare shown in the mixture delivery system 200, the skinning system 300,and the control system 400, FIG. 1 shows the systems only schematicallyfor illustrative purposes. Each system may include more or fewerelements and features than illustrated in the figures and describedherein.

As shown in FIG. 1, the mixture delivery system 200 may include aparticle analyzer 205 configured to measure a particle size distributionof a dry material, such as, for example, an inorganic powder, that is tobe used to produce a flowable mixture (e.g., a cement). The inorganicpowder may include at least one of an aluminum titanate, cordierite,fused silica, mullite, and alumina, and may have a particle size rangingfrom 1 to 1000 microns. The measured particle size distribution may beused by the control system 400 to control the properties (e.g., densityand/or viscosity) of the flowable mixture.

The particle analyzer 205 may be an in-line analyzer disposed upstreamof the blender 210. The particle analyzer 205 may be configured tomeasure data on particle sizes of the dry material. The control system400 may communicate with the particle analyzer 205 to receive data orsignals from the particle analyzer 205 with information indicating themeasured particle size distribution. The control system 400 may controlthe particle analyzer 205 by transmitting control signals to theparticle analyzer 205 to control, e.g., when to start/stop measuring theparticle size distribution. In some embodiments, the particle analyzer205 may continuously measure the particle size distribution of the drymaterial as the blender 210 receives the dry material over time, and maytransmit the measured particle size distributions to the control system400, which may determine variations in the measured particle sizedistributions over time.

As shown in FIG. 1, the mixture delivery system 200 may include ablender 210 configured to receive and blend the dry material. Themixture delivery system 200 may include a fluid dispensing system 215coupled with the control system 400 and configured to dispense ordeliver a fluid, such as, for example, water or a binder. In someembodiments, the fluid may include a combination of the water and thebinder. The binder may include any suitable binding material, such as,for example, colloidal silica in an aqueous form. The fluid dispensingsystem 215 may be configured to deliver the fluid at a rate controlledor adjusted in response to signals from the control system 400. Thecontrol system 400 may communicate with the fluid dispensing system 215to receive data or signals from various components or devices includedin the fluid dispensing system 215, and to transmit control signals tothe fluid dispensing system 215. The various components or devicesincluded in the fluid dispensing system 215 may include flow controlvalves, pumps, pressure sensors, fluid level sensors, flow meters, etc.

As shown in FIG. 1, the mixture delivery system 200 may include a mixer220, which may be any suitable type of mixer for mixing a fluid and adry material to produce a flowable mixture. In some embodiments, themixer 220 may be a continuous style mixer. The control system 400 maycommunicate with the mixer 220 to receive data or signals from the mixer220, which may include information indicating the operational status ofthe mixer 220, such as, for example, the speed of the mixer 220, thescrewfill ratio, the water call amount, etc. The control system 400 maytransmit control signals to controllable components within the mixer 220(or to a mixture control system) for adjusting mixer parameters, such asthe speed of the mixer, the screwfill ratio, the water call amount, etc.The mixer 220 may include a manual or automatic slide gate type featureat a discharging end that may be controlled manually or automatically toadjust desired flowable mixture properties, such as density and/orviscosity. Mixer element configurations (e.g., sequence of individualelements), design (e.g., shape and/or size), clearances, and material ofconstruction may be adjustable and may be configured to modify and/oroptimize flowable mixture properties (e.g., density and/or viscosity),residence time, attrition of dry materials, and/or wear rates ofconsumable components.

The feed rate (e.g., the rate of the blended material fed into the mixer220) and the rotation speed (revolutions per minute or rpm) of the mixer220 may be controlled by the control system 400 to regulate the rheologyof the flowable mixture, such as the density and/or the viscosity. Thedensity and/or viscosity may be affected by the amount of fluid (e.g.,water and/or binder) added to the mixer 220. The density and/orviscosity of the flowable mixture may also be affected by thecomposition of the dry material.

As shown in FIG. 1, the mixer 220 may be supplied with mixtureingredients (e.g., through connecting pipes, hoses, or conduits) by theblender 210 and the fluid dispensing system 215. The blender 210 maycontinuously or discontinuously blend the dry material and deliver theblended dry material to the mixer 220. The fluid dispensing system 215may dispense or deliver (e.g., through injection) an amount (orinjection rate) of the fluid into the mixer 220 based on signalsindicating a desired amount (sometimes referred to herein as a “watercall”) that may be received from the control system 400 (or a mixturecontrol system) based on sensor data from the mixer 220. The mixer 220may continuously mix the dry material and the fluid to produce theflowable mixture, such as, for example, cement for skinning to a ceramicarticle (e.g., a diesel particulate matter filter substrate).

As shown in FIG. 1, the mixture delivery system 200 may include astorage device 225 configured to temporarily store the flowable mixtureproduced by the mixer 220. The storage device 225 may also be referredto as a hopper or a surge hopper. The storage device 225 may be disposeddownstream of the mixer 220 and coupled (e.g., through connecting pipes,hoses, or conduits) with the mixer 220 to receive the flowable mixturefrom the mixer 220.

The storage device 225 may include a load cell 230 configured to measurethe weight of the flowable mixture stored in the storage device 225and/or the weight of the flowable mixture that has been discharged fromthe storage device 225. The load cell 230 may be a loss-in-weight loadcell, which may provide an amount of the flowable mixture that has beendischarged from the storage device 225. The load cell 230 may transmitdata or signals to the control system 400 to provide the control system400 with the amount of flowable mixture that has been discharged.

The storage device 225 may include a vibration device 231 attached to arib of the storage device 225 on an outer surface. The vibration device231 may be configured to cause the storage device 225 to vibrate or moveback and forth or side-to-side or circularly, thereby aiding in thedownward flow of the flowable mixture.

The control system 400 may communicate with various controllable devicesand components (e.g., the load cell 230 and/or the vibration device 231)included in the storage device 225 to receive data or signals includingmeasurement data and information regarding the operational status of thecomponents within the storage device 225 (e.g., the amount of flowablemixture that has been discharged from the storage device 225). Thecontrol system 400 may transmit control signals to various components ordevices within the storage device 225, such as the load cell 230 and/orthe vibration device 231.

As shown in FIG. 1, the mixture delivery system 200 may include a pump235 configured to advance the flowable mixture from the storage device225 to a delivery line 240. The pump 235 may be any pump suitable foradvancing the flowable mixture through the mixture delivery system withdesirable flow rates and pressure to operate the skinning system 300. Insome embodiments, the pump 235 may be a progressive cavity pump. Theprogressive cavity pump 235 may be configured for high torque and lowrpm to reduce wear and still allow accurate pressure control of flowablemixture delivery to the manifold without major pulses in pressure. Othertypes of pumps may also be capable of achieving these to a lesser degreeand for a variety of reasons. Examples of other types of pumps mayinclude peristaltic/hose pumps, gear pumps, piston pumps, or alternatingdual piston pumps. The control system 400 may communicate with the pump235 to receive signals or data from the pump 235 including informationindicating the operational status of the pump 235, such as the speed ofthe pump 235, the pressure within the pump 235, etc.

As shown in FIG. 1, the delivery line 240 may include one or morepressure sensors disposed at various locations and configured to measurepressures within the delivery line 240. For example, the delivery line240 may include a pressure sensor 250 configured to measure a pressureof the pump 235 (pump pressure). The pressure sensor 250 may be disposedwithin the pump 235 or downstream of the pump 235 in the delivery line240 (e.g., adjacent an outlet of the pump 235). The pressure sensor 250may be disposed at any other suitable locations within the mixturedelivery system 200. The control system 400 may communicate with thepressure sensor 250 to receive data or signals including informationindicating the measured pump pressure. The control system 400 maytransmit control signals to the pressure sensor 250 to control when tomeasure the pressure, and/or when to transmit the measured pressure tothe control system 400.

As shown in FIG. 1, the delivery line 240 may also include a pressuresensor 255 configured to measure a pressure within the delivery line240. The pressure measured by the pressure sensor 255 may be referred toas the delivery pressure or delivery line pressure. The pressure sensor255 may be disposed within, adjacent, or downstream of the deliveryvalve 245. The delivery pressure may reflect the pressure of theflowable mixture prior to being delivered to the skinning system 300.The control system 400 may communicate with the pressure sensor 255 toreceive data or signals including information indicating the measureddelivery pressure. The control system 400 may transmit control signalsto the pressure sensor 255 to control, for example, when to measure thedelivery pressure and/or when to transmit the measured delivery pressureto the control system 400.

The control system 400 may transmit control signals to the pump 235 tocontrol various parameters, such as at least one of the speed of thepump 235, the pressure within the pump 235 and/or the delivery line 240,and may do so in response to pressure data received from the pressuresensors 250, 255. The rotation speed (rpm or revolutions per minute) ofthe pump 235 may be controlled by the control system 400 to ensure asubstantially consistent flowable mixture pressure provided to or withinthe skinning system 300. In some embodiments, control system 400, thepump 235, the skinning system 300 and the piping in between may beconfigured so that the pump 235 regulates the pressure within theskinning system 300 (such as the manifold pressure and/or pressurewithin the skinning pipe), and may be operated so that the flowablemixture is applied to unskinned articles at a substantially consistentpressure. In other embodiments, the skinning system 300 may include itsown pressure regulator subsystem, in which case the pump 235 may providethe flowable mixture at a pressure suitable for supplying that pressureregulatory subsystem. The flow rate and/or the pressure of the flowablemixture within the delivery line 240 may be regulated by the controlsystem 400 controlling the speed and/or displacement of the pump 235.The pump 235 may include a stator that is suitable for long timeoperations, such as non-stop continuous operations. In some embodiments,the pump 235 may include a poly-urethane stator (not shown).

As shown in FIG. 1, in some embodiments, the mixture delivery system 200may include a recirculation line 260 configured to continuouslyrecirculate at least a portion of the flowable mixture. Therecirculation line 260 may redirect or return at last a portion of theflowable mixture from the delivery line 240 back to the storage device225. The storage device 225 may include a port configured to receive therecirculated portion of the flowable mixture. The recirculation line 260enables the mixer 220 to run continuously at a reduced, low feed ratewhen the skinning system 300 is not started or has been paused orstopped so that the flowable mixture does not settle. For example, whenthe skinning system 300 is stopped or paused temporarily (e.g., forchanging sub-components or for cleaning or repair), the mixer 220 maycontinue to run at a reduced speed and/or feed rate with the flowablemixture being recirculated using the recirculation line 260 to preventsettling of the flowable mixture (e.g., cement). In some embodiments,the recirculation line 260 may enable the flowable mixture to berecirculated without settling for one to three hours. The storage device225 may or may not be included in the mixture delivery system 200. Ifthe storage device 225 is included, it may take on a variety of shapesand sizes, depending on the use. Examples of the storage device 225 mayinclude a simple cone, a stirred cone, a rectangular chute, a vibratedtube, or any combination of shape, size, and feature.

As shown in FIG. 1, the delivery line 240 may include a delivery valve245. In some embodiments, the delivery valve 245 may be a two-waydelivery valve, while in other embodiments the delivery valve 245 may bea configuration of multiple one-way valves and interconnecting pipes.The control system 400 may communicate with the delivery valve 245 toreceive data or signals including information indicating the position(e.g., opening) of the delivery valve 245. The control system 400 maytransmit control signals to actuators on the delivery valve 245 toadjust its position.

By controlling the position of the delivery valve 245, the controlsystem can regulate the fraction of the flowable mixture that passes tothe skinning system 300 and the fraction that is recirculated to themixing delivery system 200, thereby regulating the amount of flowablemixture delivered to the downstream skinning system 300. Referring toFIG. 1, the two-way delivery valve 245 may be positioned (e.g., theopening of the valve 245 may be adjusted) to regulate an amount offlowable mixture flowing to the skinning system 300 and the amountflowing through the recirculation line 260. For example, the position ofthe two-way delivery valve 245 may be adjusted such that all flowablemixture flows to the skinning system 300, all flowable mixture flows tothe recirculation line 260, or a first portion of the flowable mixtureflows to the skinning system 300 and a second portion of the flowablemixture flows to the recirculation line 260.

Although not shown in FIG. 1, in some embodiments, the recirculationline 260 may return at least a portion of the flowable mixture to themixer 220 instead of or in addition to the storage device 225. Therecirculation line 260 may include a pressure sensor 265 configured tomeasure a pressure within the recirculation line 260, which may bereferred to as a return pressure. The pressure sensor 265 may bedisposed within the recirculation line 260 at a suitable location. Forexample, the pressure sensor 265 may be disposed downstream of thedelivery valve 245 in the recirculation line 260. The control system 400may communicate with the pressure sensor 265 to receive data or signalsincluding information indicating the measured return pressure. Thecontrol system 400 may transmit control signals to the pressure sensor265 to control, for example, when to measure the return pressure and/orwhen to transmit the measured return pressure to the control system 400.

The recirculation line 260 may include a reducer 270 configured toregulate the flow of the flowable mixture. The reducer 270 may beoptional and not included in all embodiments. The recirculation line 260may further include a valve 275, which may be referred to as a returnvalve 275. The return valve 275 may be any suitable flow control valve,and may be configured to control the amount of flowable mixture flowingwithin the recirculation line 260. The return valve 275 may becontrolled by the control system 400 in order to control back or returnpressure within the recirculation line 260. The position of the deliveryvalve 245 may be controlled by the control system 400 to regulate themanifold pressure or the skinning pipe pressure. For example, thecontrol system 400 may communicate with the return valve 275 to receivedata or signals including information indicating the position of thereturn valve 275. The control system 400 may transmit control signals toactuators of the return valve 275 to adjust its position, therebyregulating the return pressure within the recirculation line 260 and/orthe amount of flowable mixture flowing within the recirculation line260, which may affect the manifold pressure or the skinning pipepressure.

In some embodiments, the control system 400 may control the speed of thepump 235 and the position of the delivery valve 245 and the return valve275 together in order to regulate the amount of flowable mixture and thepressure of the flowable mixture delivered to downstream skinning system300.

As shown in FIG. 1, the mixture delivery system 200 may include a purgeline 280 in addition to or instead of the recirculation line 260. Thepurge line 280 may include a valve 285 configured to regulate an amountof the flowable mixture flowing within the purge line 280. The valve 285may be any suitable flow control valve, and may be controlled by thecontrol system 400. For example, the control system 400 may communicatewith the valve 285 to receive data or signals including informationindicating the position of the valve 285. The control system 400 maytransmit control signals to the valve 285 to adjust the position,thereby controlling the amount of flowable mixture flowing in the purgeline 280.

The purge line 280 may include a pressure sensor 290 configured tomeasure a pressure in the purge line 280. The pressure sensor 290 may bedisposed at any suitable location within the purge line 280, such asdownstream of the valve 285 or upstream of the valve 285. The controlsystem 400 may communicate with the pressure sensor 290 to receive dataor signals including information indicating the measured pressure. Thecontrol system 400 may transmit control signals to the pressure sensor290 to control, for example, when to measure the pressure and/or when totransmit the measured pressure to the control system 400.

Although not shown in FIG. 1, the purge line 280 may be connected to atote or other container (not shown) for receiving the purged (e.g.,dumped) flowable mixture. In some embodiments, when at least oneproperty (e.g., density and/or viscosity) of the flowable mixture do notmeet target requirements, the purge line 280 may be used to dump ordiscard the flowable mixture. In some embodiments, the purge line 280may be used to redirect the flowable mixture from the delivery line 240until the properties of the mixture and the pressure in the deliveryline 240 satisfy operational parameters to enable activation of theskinning system 300 to receive the flowable mixture. When the purge line280 is open (e.g., when the valve 285 is open), the delivery valve 245may be closed to prevent the flowable mixture from flowing to theskinning system 300.

As shown schematically in FIG. 1, the skinning system 300 may include askinning pipe 310 that is supported by a manifold 305. The term“manifold assembly” may include the manifold 305 and various devices orcomponents mounted on or to the manifold 305 and/or the skinning pipe310. The manifold assembly may also include various devices orcomponents provided around the manifold 305. In some embodiments,various devices or components mounted on or to the manifold 305 may beregarded as parts of the manifold 305. Thus, manifold 305 may also bereferred to as manifold assembly 305. In some embodiments, the skinningpipe 310 may be mounted in a hole located at a center portion of themanifold 305. The skinning pipe 310 may define an inner space to receivean article (e.g., article 311 or 312). The skinning system 300 may applythe flowable mixture to the article through the skinning pipe 310, asthe article moves axially within the inner space of the skinning pipe310. For example, as an article moves along the inner space of theskinning pipe 310 in an upward direction (from bottom to top), thearticle may receive the flowable mixture at its outer surface.

FIG. 1 shows three articles 311, 312, and 313, among which the article313 is an unskinned article, and the articles 311 and 312 are at leastpartially skinned articles (e.g., at least partially being applied withthe flowable mixture on their respective outer surfaces). The articles311, 312, and 313 may be inserted or pushed into the skinning pipe 310by an article feeding mechanism 315, which may be disposed below theskinning pipe 310 in a vertical direction. The article feeding mechanism315 may be configured to center and/or align an unskinned article (e.g.,article 313) with the skinning pipe 310 before or while pushing thearticle into the skinning pipe 310.

As schematically shown in FIG. 1, the skinning system 300 may include atransfer system 320 configured to hold an article exiting the skinningpipe 310 (e.g., article 311) and move the article out of the skinningpipe 310. For illustrative purposes, a vacuum system is shown as anexample of the transfer system 320. For discussion purposes, thetransfer system 320 is referred to as a vacuum system 320. The vacuumsystem 320 may hold and move the article out of the skinning pipe 310using a vacuum pressure or vacuum force. While the vacuum system 320holds the article using the vacuum pressure, the vacuum system 320 maypull one or more articles (e.g., article 311 or both articles 311 and312) in an upward direction through the skinning pipe 310, as the one ormore articles move axially within the inner space of the skinning pipe310 to receive the flowable mixture. The vacuum system 320 may work incombination with the article feeding mechanism 315 so that articles arepushed up through the skinning pipe 310 from the bottom by the articlefeeding mechanism 315 and pulled out of the top of the skinning pipe 310by the vacuum system 320. Alternatively, the vacuum system 320 mayfunction merely to lift articles from the skinning pipe 310 after theyhave been pushed through the skinning pipe 310 by the article feedingmechanism 315 applying a pushing force from the bottom.

As shown in FIG. 1, the manifold 305 may include one or more pressuresensors 325 mounted thereon to measure a pressure associated with themanifold (which may be referred to as a “manifold pressure”). Forexample, the manifold pressure may refer to the pressure at an inlet ofthe manifold 305, where the flowable mixture from the mixture deliverysystem 200 is received and directed into distribution channels withinthe manifold 305. Although FIG. 1 only shows that the mixture deliverysystem 200 is connected to one side of the manifold 305 for deliveringthe flowable mixture to the manifold 305, the mixture delivery system200 may also be connected to other locations of the manifold 305 so thatthe manifold 305 may receive the flowable mixture from the mixturedelivery system 200 through more than one inlet.

As shown in FIG. 1, the skinning system 300 may include one or morepressure sensors 330 configured to measure a pressure of the flowablemixture at a flow inlet of the skinning pipe 310, where flowable mixtureis received from the manifold 305 and is about to flow into the innerspace of the skinning pipe 310 for applying to the article. The pressuremay be referred to as a skinning pipe pressure, a unipipe pressure, apressure of the pipe, or a pressure of the skinning pipe. The pressuresensors 330 may be mounted to the skinning pipe 310 at a suitablelocation. For example, the pressure sensors 330 may be mounted to alower portion of the skinning pipe 310 that is below a lower surface ofthe manifold 310.

As shown in FIG. 1 and described above, the control system 400 maycommunicate with the mixture delivery system 200 and the skinning system300, and may control the operations of the mixture delivery system 200and the skinning system 300. The control system 400 may communicate withvarious components or devices included in the mixture delivery system200 and/or the skinning system 300. The control system 400 may receivesignals or data from the mixture delivery system 200 and/or the skinningsystem 300, and may transmit control signals to the mixture deliverysystem 200 and/or the skinning system 300 to control their operations.

The control system 400 may include various hardware and/or softwarecomponents, modules, units, etc. The hardware components may includecircuits, processors, and memories. The software components within thecontrol system may include computer-implemented programs or modules madeup of computer executable instructions and/or codes.

The control system 400 may include at least one processor 415 and atleast one memory 420. The processor 415 may be any suitable computerprocessor, such as, for example, a central processing unit (CPU), asignal processor, etc. The memory 420 may be any suitable memoryconfigured to store programs, instructions, and/or codes, which may beexecuted by the processor 415. The memory 420 may be a non-transitory ortangible random access memory (RAM), a read-only memory (ROM), a flashmemory, etc. The processor 415 may read the instructions and/or codesfrom the memory 420 and execute the instructions and/or codes to runprograms that perform various control system functions, such as themethods or processes disclosed herein.

In some embodiments, the control system 400 may be implemented assoftware and stored on a tangible, non-transitory computer-readablemedium, such as a hard-disk, a compact disc, a flash memory, etc. Asshown in FIG. 1, the control system 400 may include a mixture controlsystem module 405 and a skinning control system module 410, which may beimplemented as separate software modules executing on a centralprocessor 415, or as modules executing on separate processorscommunicating with a central processor. Within embodiments describedabove in which the mixture delivery system 200 and the skinning system300 are configured with their own control systems, the mixture controlsystem module 405 and a skinning control system module 410 may beimplemented on separate processors positioned within or nearby theirrespective systems and communicating via cable or network connectionswith the central processor 415.

In some embodiments, the mixture control system 405 and/or the skinningcontrol system 410 may each include control hardware components,software components, or both. For example, the mixture control system405 and the skinning control system 410 may each include hardwarecircuits, processors, memories, and communication units.

As shown in FIG. 1, the control system 400 may include a communicationunit 425 configured to enable the control system 400 to communicate withvarious components or devices included in the mixture delivery system200 and the skinning system 300. The communication unit 425 may be alocal area data network or a plurality of wired or wirelesscommunication links to various components configured to enable thecontrol system 400 to receive data or signals from the mixture deliverysystem 200 and/or the skinning system 300, and transmit control signalsto the mixture delivery system 200 and the skinning system 300 tocontrol their operations.

In some embodiments, the communication unit 425 may communicate with themixture delivery system 200 through number of data connection cables ora communication network 430. Similarly, the communication unit 425 maycommunicate with the skinning system 300 through number of dataconnection cables or a communication network 435. The communicationnetworks 430 and 435 may be different or the same. The communicationnetworks 430 and 435 may be wired or wireless networks (e.g., Wi-Fi,Bluetooth, etc.). The communication unit 425 may be configured toreceive signals or data (e.g., measured system parameters) from themixture delivery system 200 and the skinning system 300, and transmitsignals (e.g., control signals) to the mixture delivery system 200 andthe skinning system 300 through their respective networks 430, 435. Thecommunication unit 425 may include hardware components, softwarecomponents, or both. For example, the communication unit 425 may includeswitches, routers, Ethernet ports, wireless transceivers, communicationlines, etc.

The interconnection among the various components included in the controlsystem 400 (e.g., the mixture control system 405, the skinning controlsystem 410, the processor 415, and the memory 420) is only forillustrative purposes. Components included in the control system 400 maybe connected with one another and may communicate with one another.

FIG. 2 is a flowchart illustrating an exemplary method (or process) 500for operating the system 100 for skinning the articles. The method 500may be performed by the mixture delivery system 200 and the skinningsystem 300 working in concert under direction of the control system 400that receives data from measuring devices and sends control signals tocontrollable components and subsystem within the system 100. The method500 may include activating and running the mixture delivery system 200to produce and deliver a flowable mixture (block 505). The mixturedelivery system 200 may be managed and controlled by the mixture controlsystem 405 that may be activated (block 510). The method 500 may includedetermining whether the skinning process should be started (step 515).Various factors may be considered or evaluated in determining whetherthe skinning process should be started. Such factors may include thestatus of the skinning system 300, e.g., whether the skinning system 300has been assembled and tuned, the skinning pipe pressure, etc. Thefactors may also include the status of the mixture delivery system 200,e.g., whether the properties of the flowable mixture meet the targetrequirements, whether the return pressure within the recirculation line260 has reached a threshold return pressure value, or whether thedelivery pressure in the delivery line 240 has reached a thresholddelivery pressure value, etc.

Until the control system 400 determines that the skinning process shouldbe started (No, block 515), the mixture delivery system 200 may beoperated to prepare the mixture and keep the mixture ready for usewithout starting the skinning process (e.g., by recirculating theflowable mixture in the recirculation line 260). When the control system400 determines that the skinning process should be started (Yes, block515), the skinning process may be started to receive the flowablemixture and start skinning the articles with the flowable mixture (block520), and the skinning control system 410 may be activated to controlthe skinning system 300 (block 525). The skinning system 300 may beactivated before the skinning process is started, or may be activated atthe same time the skinning process is started. The mixture deliverysystem 200 and the skinning system 300 may continuously andautomatically run to produce the flowable mixture and apply the flowablemixture to the articles until some events (e.g., scheduled maintenance,repairs, unexpected sudden stoppage) causes the control system 400 tostop the mixture delivery system 200 and/or the skinning system 300.

FIG. 3 is a flowchart showing an exemplary method 600 for operating thesystem 100. The method 600 may include mixing a dry material with afluid in a mixer (e.g., the mixer 220) to produce a flowable mixture(block 605). The method 600 may include pumping (e.g., by the pump 235)the flowable mixture to the skinning system 300 through the deliveryline 240 (block 610). The method 600 may include aligning an article(e.g., an unskinned article 313) with the skinning pipe 310 using thearticle feeding mechanism 315. The method 600 may include pushing thearticle into an inner space of the skinning pipe 310 (block 620).

The method 600 may include applying the flowable mixture to the articleusing the skinning pipe 310 (block 625). The flowable mixture may beapplied to the article by the skinning pipe 310 as the article movesaxially along the inner space of the skinning pipe 310. The axialmovement of the article may be upward in a vertical direction (e.g.,against the gravity of the article). The method 600 may include holdingthe article by a vacuum pressure generated by the vacuum system 320, asthe article moves axially along the inner space of the skinning pipe 310to receive the flowable mixture (block 630). The method 600 may alsoinclude moving the article out of the skinning pipe 310 using the vacuumsystem 320 while the vacuum system 320 holds the article with the vacuumpressure, as the article moves axially along the inner space of theskinning pipe 310 to receive the flowable mixture (block 635).

FIGS. 4 and 5 are a flowchart showing an exemplary method 700 foroperating the system 100. The method 700 may include mixing a drymaterial with a fluid in a mixer (e.g., the mixer 220) to produce aflowable mixture (block 705). The method 700 may include pumping (e.g.,by the pump 235) the flowable mixture to the skinning system 300 throughthe delivery line 240 (block 710). The method 700 may include measuringa particle size distribution of the dry material (block 715). In someembodiments, the particle analyzer 205 may measure the particle sizedistribution. The method 700 may include determining, using a first feedforward controller, an adjustment to an amount of the fluid to be addedto the mixer 220 based on a variation in the particle size distribution(block 720). The fluid may include at least one of water or a suitablebinder.

The method 700 may include measuring at least one of a density or aviscosity of the flowable mixture in the delivery line 240 (block 725).The method 700 may include determining, using at least one firstfeedback controller, at least one of the amount of fluid (e.g., waterand/or binder) to be added to the mixer 220 or a screwfill ratio of themixer 220, based on at least one of the measured density or the measuredviscosity (block 730). The method 700 may include measuring a variationin at least one of the viscosity, a flow rate of the flowable mixture(e.g., within the delivery line 240), or dimensions (e.g., diameter,radius, circumference, axial length, and/or outer peripheral length) ofincoming unskinned articles (block 735). Measuring the variation in theat least one of the viscosity, flow rate, or dimensions of the incomingunskinned articles may include measuring the viscosity, flow rate, orthe dimensions, and determining a variation over time.

Referring to FIG. 5, the method 700 may include determining, using asecond feed forward controller, an adjustment to at least one of adelivery pressure set point, a return pressure set point, a speed of thepump (e.g., pump 235), a delivery valve position (e.g., position of thedelivery valve 245), a flow rate set point, a skinning speed associatedwith the skinning system 300, or a pressure relief system position,based on the variation in at least one of the measured viscosity, theflow rate, or the dimensions (e.g., diameter, radius, circumference,axial length, and/or outer peripheral length) of the incoming unskinnedarticles (block 740). The method 700 may include measuring a skinningpipe pressure at the skinning pipe 310 that applies the flowable mixtureto the article (block 745).

The method 700 may include monitoring presence of a defect from askinned article coated with the flowable mixture (block 750). Monitoringthe presence of the defect may include detecting a type of the defect ifthe defect is present. The type of defect may be a fast flow defect, astarvation defect, a pit defect, a pock defect, or a ring defect. Thetype of defect may be determined based on different signals associatedwith different types of defects, such as signals with different peakmagnitudes, frequencies, pixel characteristics, etc.

The method 700 may include determining, using at least one secondfeedback controller, at least one of a skinning pipe pressure set point,the delivery pressure set point, the return pressure set point, thespeed of the pump (e.g., pump 235), the delivery valve position (i.e.,the position of the delivery valve 245), or the flow rate set point,based on a result of monitoring the presence of the defect. For example,the result of monitoring the presence of the defect may include a typeof defect determined from a detected defect. Thus, in some embodiments,the method 700 may include determining, using at least one secondfeedback controller, at least one of a skinning pipe pressure set point,the delivery pressure set point, the return pressure set point, thespeed of the pump (e.g., pump 235), the delivery valve position (i.e.,the position of the delivery valve 245), or the flow rate set point,based on the type of defect detected from a skinned article. The method700 may further include transmitting a control signal to at least one ofthe mixture delivery system 200 or the skinning system 300 based on anoutput from at least one of the first feed forward controller, thesecond feed forward controller, the at least one first feedbackcontroller, or the at least one second feedback controller (block 760).

Mixture Delivery Systems and Controls

FIG. 6 schematically shows another embodiment of the system 100 includeadditional components of the mixture delivery system 200 and the mixturecontrol system 405. Some of the components included in the mixturedelivery system 200 have been described above in connection with FIG. 1.

In some embodiments, the mixture delivery system 200 may include adensitometer 295 configured to measure the density of the flowablemixture. The densitometer 295 may be an in-line densitometer, and may bedisposed at any suitable location within the delivery line 240. Forexample, the densitometer 295 may be disposed downstream of the deliveryvalve 245, upstream of the delivery valve 245, or downstream of the pump235. The densitometer 295 may also be disposed at other locations, suchas, for example, upstream of the pump 235, within the recirculation line260, within the purge line 280, or within the skinning system 300. Theinline densitometer 295 may be a radiometric device.

As described above, the mixture control system 405 may be part of thecontrol system 400 or may be a dedicated, separate control system. Themixture control system 405 may communicate with the densitometer 295 viacables or a network 430 to receive signals or data including informationindicating the measured density of the flowable mixture, and transmitcontrol signals to the densitometer 295 such as to control when tomeasure the density and/or when to transmit the measured density to themixture control system 405. The skinning control system 410 may alsoobtain the measured density from either the mixture control system 405or the densitometer 295. The mixture control system 405 and/or theskinning control system 410 may use the measured density to control theproperties of the flowable mixture and/or the skinning process.

As shown in FIG. 6, the mixture delivery system 200 may include aviscometer 296 configured to measure the viscosity of the flowablemixture. The viscometer 296 may be an in-line viscometer, and may bedisposed at any suitable location within the mixture delivery system200. For example, the viscometer 296 may be disposed within the deliveryline 240. In some embodiments, the viscometer 296 may be disposeddownstream of the delivery valve 245, upstream of the delivery valve245, downstream of the pump 235, etc. The viscometer 296 may also bedisposed at other locations, such as, for example, upstream of the pump235, within the recirculation line 260 or the purge line 280, or withinthe skinning system 300. The mixture control system 405 may communicatewith the viscometer 296 via cables or a network 430 to receive signalsor data including information indicating the measured viscosity of theflowable mixture, and transmit control signals to the viscometer 296such as to control when to measure the viscosity and/or when to transmitthe measured viscosity to the mixture control system 405. The skinningcontrol system 410 may also obtain the measured viscosity from eitherthe mixture control system 405 or the viscometer 296. The measuredviscosity may be used by the mixture control system 405 and/or theskinning control system 410 to control the properties of the flowablemixture and/or the skinning process, respectively.

As shown in FIG. 6, the mixture delivery system 200 may include a flowmeter 297 configured to measure a flow rate of the flowable mixture. Theflow meter 297 may be any suitable flow meter, such as a flow meter witha summation function for calculating the total amount of flow. The flowmeter 297 may be disposed within the delivery line 240 to measure theflow rate within the delivery line 240. The flow meter 297 may be anin-line flow meter, and may be disposed at any suitable location withinthe delivery line 240. For example, one or more flow meters 297 may bedisposed downstream of the delivery valve 245, upstream of the deliveryvalve 245, downstream of the pump 235, etc. The mixture control system405 may communicate with the flow meter(s) 297 via cables or a network430 to receive signals or data including information indicating themeasured flow rate of the flowable mixture, and transmit control signalsto the flow meter 297 such as to control when to measure the flow rateand/or when to transmit the measured flow rate to the mixture controlsystem 405. The skinning control system 410 may also obtain the measuredflow rate from either the mixture control system 405 or the flow meter297. The measured flow rate may be used by the mixture control system405 and/or the skinning control system 410 to control the properties ofthe flowable mixture and/or the skinning process, respectively.

As shown in FIG. 6, the mixture delivery system 200 may include arheometer 298 configured to measure the rheology of the flowablemixture. The rheology of the flowable mixture may relate to the behaviorof the flowable mixture. The rheology may include various parameters,such as, for example, the mixture consistency, viscosity, density, andcharacteristics associated with shear stress and/or shear strain,extensional stress and/or extensional strain, etc. In some embodiments,the rheometer 298 may measure the consistency of the flowable mixture.In some embodiments, the rheometer 298 may also measure the densityand/or the viscosity. The rheometer 298 may be an in-line rheometer, andmay be disposed at any suitable location, such as, for example,downstream of the pump 235 in the delivery line 240, downstream of thedelivery valve 245, etc. The rheometer 298 may be used as an alternativeto the densitometer 295 and/or the viscometer 296, or may be used incombination with the densitometer 295 and/or the viscometer 296.

The mixture control system 405 may communicate with the rheometer 298via cables or a network 430 to receive signals or data includinginformation regarding the measured rheology of the flowable mixture, andtransmit control signals to the rheometer 298 such as to control when tomeasure the rheology and/or when to transmit the measured rheology tothe mixture control system 405. The skinning control system 410 may alsoobtain the measured rheology from either the mixture control system 405or the rheometer 298. The measured rheology may be used by the mixturecontrol system 405 and/or the skinning control system 410 to control theproperties of the flowable mixture and/or the skinning process,respectively.

As shown in FIG. 6, in some embodiments, the exemplary mixture controlsystem 405 may include a processor 440, a memory 445, and acommunication unit 450. The communication unit 450 may be a dedicatedcommunication unit for the mixture control system 405, which may be thesame as or similar to the communication unit 425 shown in FIG. 1. Insome embodiments, the communication unit 450 may be part of thecommunication unit 425 shown in FIG. 1. The processor 440 and the memory445 may be dedicated processor and memory for the mixture control system405, or may be the same as or similar to the processor 415 and memory420 shown in FIG. 1. In some embodiments, the processor 440 and memory445 may be part of the processor 415 and memory 420 shown in FIG. 1.

The mixture control system 405 may also communicate with the skinningsystem 300 via a network 431, which may include a wired and/or wirelessnetwork. For example, the mixture control system 405 may receive data orsignals from various components included in the skinning system 300, andmay transmit control signals to the various components in the skinningsystem 300.

FIG. 7 schematically shows an exemplary configuration of the mixturedelivery system 200. In addition to the components shown in FIG. 1 anddescribed above, FIG. 7 shows other components that may be included inthe mixture delivery system 200. The mixture delivery system 200 mayinclude a dry blend feeder 805 configured to receive blended drymaterial from the blender 210 and feed the blended dry material to themixer 220. The dry blend feeder 805 may be disposed downstream of theblender 210 and upstream of the mixer 220. The dry blend feeder 805 maybe a loss-in-weight feeder, and may be controlled by the control system400 (e.g., the mixture control system 405). For example, the controlsystem 400 may communicate with the dry blend feeder 805 via cables or anetwork 430 to receive signals or data including information indicatingthe amount of dry material that has been fed to the mixer 220. Thecontrol system 400 may transmit control signals to the dry blend feeder805 via cables or a network 430 to control the amount to be fed to themixer. In some embodiments, the dry blend feeder 805 may operate at afeed rate between 0-500 lbs/hour. In some embodiment, the dry blendfeeder 805 may be part of or integral with the blender 210.

Referring to FIG. 7, a measuring device, such as a scale or load cell(not shown), within the blender 210 may weigh the desired amounts of rawmaterials (e.g., two, three, or four raw materials) before or while theblender 210 dry blends raw materials together. In some embodiments, thecomposition of the raw materials may comprise 70%/30% “coarse”/“fine”fused silica, 10% Wollastonite, and 1% cellulosic binder. Once blended,the blended dry material may be fed to the continuously runningloss-in-weight dry blend feeder 805. When the feeder 805 is beingrefilled, the loss-in-weight control feature may be disabled and the dryblend feeder 805 may use a “volumetric” feed to keep a screw speed ofthe feeder 805 substantially constant in a continuous operation mode.The feed rate of the dry blend feeder 805 may range from 50 to 300lbs/hour. In some embodiments, the feed rate of the dry blend feeder 805may range from 0 to 500 lbs/hour. The feed rate of the dry blend feeder805 may be controlled such that the downstream flow rate of the flowablemixture within the delivery line 240 may range from 50 to 300 lbs/hour,such as 50 to 200 lbs/hours.

Referring to FIG. 7, in some embodiments, the fluid dispensing system215 may include one or more (e.g., two) liquid systems for dispensingone or more liquids, such as water and colloidal silica suspension, tothe mixer 220 or a fluid tote or container. The fluids may becontinuously fed to the mixer 220. The fluid dispensing system 215 mayinclude at least one of a flow meter, a pump, a flow control valve toaccurately dispense fluids at target rates. The fluid dispensing ratemay range from 50 to 300 pounds/hour. In some embodiments, the fluiddispensing rate may range from 0 to 500 pounds/hour.

As described above, the pump 235 may be operated under direction of thecontrol system 400 to regulate the flow of the flowable mixture throughthe delivery line 240. The pump 235 may include a motor/gearbox, achromed rotor, and a polyurethane stator. In various embodiments, thepump 235 may be a progressive cavity pump, a hose (or peristaltic) pump,a diaphragm pump, a gear pump, or a circumferential piston pump. Thestator of a progressive cavity pump may be replaceable, allowingconvenient replacement of consumable part in addition to more precisecontrol of flowable mixture (e.g., cement) through pump speed control(e.g., rpm manipulation).

FIG. 7 represents an exemplary vertical layout of the components of themixture delivery system 200. In some embodiments, the blender 210 may bedisposed at 21-27 feet above the ground/floor. The fluid dispensingsystem 215 may be disposed at 15-18 feet above the ground/floor. The dryblend feeder 805 may be disposed at 14-17 feet above the ground/floor.The mixer 220 may be disposed at 12-13 feet above the ground/floor. Thestorage device 225 may be disposed 6-11 feet above the ground/floor. Therecirculation line 260 and the delivery line 240 may be disposed at 5-8feet above the ground/floor. The pump 235 may be disposed at 4-6 feetabove the ground/floor.

FIGS. 8A and 8B show an exemplary mixer head 810 that may be used in themixer 220. The continuous mixer 220 may be used to mix both dry and wetingredients (e.g., the dry blend and the fluids) together into a uniformpaste-like flowable mixture (e.g., cement). The size of the mixer 220may be determined by a target feed rate. The rheology of the producedflowable mixture (e.g., cement) may be affected by the processingparameters and hardware setup used in the mixer 220. Feed rate and speed(e.g., rpm) of the mixer 220 may be adjusted independently, such as tomaintain a certain ratio between the feed rate and the speed (e.g., ascrewfill ratio) to maintain a substantially consistent density of theflowable mixture. The element configuration and gate opening thatregulates the output of the mixer 220 may also affect the rheology ofthe flowable mixture. In some embodiments, the mixer 220 may be a mixerfrom Readco Kurimoto LLC. In some embodiments, the mixer may be a mixermade by Gabler GmbH & Co. KG, Bepex International LLC, etc.

FIG. 9 schematically shows an exemplary fluid dispensing system 215. Thefluid dispensing system 215 may be used for a continuous skinningprocess or a batch-wise (e.g., index mode) skinning process. The fluiddispensing system 215 may be used for systems and processes other thanthe mixture delivery system 200 and the mixing process. The fluiddispensing system 215 may include a storage tank 820 configured to storeone or more fluids (e.g., water, colloidal silica suspension, etc.). Thefluid dispensing system 215 may include a pump 825 configured to pumpthe fluid from the storage tank 820 to a recirculation loop 835. Thepump 825 may be referred to as a fluid system pump 825. The pump 825 maybe in fluid communication with the storage tank 820 through a conduit830. The fluid dispensing system 215 may include one or more pressuresensors (e.g., pressure sensors 840 and 850) configured to measure apressure of the fluid within the recirculation loop 835.

The fluid dispensing system 215 may include a filter 845 disposed withinthe recirculation loop 835 and configured to filter contaminants out ofthe fluid. The filter 845 may be any suitable filter. In someembodiments, the filter 845 may be a screen type filter. The pressuresensor 840 may be disposed upstream of the filter 845 and may bereferred to as a pre-filter pressure sensor 840. The pressure sensor 850may be disposed downstream of the filter 845 and may be referred to as apost-filter pressure sensor 850. The difference between the pressuremeasured by the pre-filter pressure sensor 840 and the pressure measuredby the post-filter pressure sensor 850 may indicate whether the filter845 needs to be cleaned or replaced. The pre-filter pressure sensor 840may have a higher pressure reading than the post-filter pressure sensor850. In some embodiments, during normal operations, there may be a 10psi pressure difference between the pre-filter pressure sensor 840 andthe post-filter pressure sensor 850. In some embodiments, when thepressure difference reaches or exceeds 20 psi, an alarm may beinitiated, indicating that the filter 845 should be cleaned, replaced,or otherwise serviced.

Referring to FIG. 9, the fluid dispensing system 215 may include a flowmeter 855 disposed in the recirculation loop 835, which may be referredto as a delivery system flow meter. The flow meter 855 may measure thefluid flow rate within the recirculation loop 835. The fluid dispensingsystem 215 may include a pressure sensor 860, which may be referred toas a supply header pressure sensor. The regions between the deliverysystem flow meter 855 and the supply header pressure sensor 860 may bereferred to as a supply header region 836, and may receive connectionsof distribution branches for delivering fluids to various users (such asmixers or totes). The pressure sensor 860 may be configured to measure apressure within the supply header region 836, which may also be referredto as the back pressure.

The fluid dispensing system 215 may include a flow control valve 865,which may be any suitable flow control valve, such as a proportionalflow control valve 865. The proportional flow control valve 865 mayincrementally control or modulate an amount of flow of the fluid withinthe recirculation loop 835 by adjusting its opening within the range of0% to 100%. The proportional flow control valve 865 may be completelyclosed (0% opening) or be opened at any suitable amount between 0% and100% (i.e. completely open). The proportional flow control valve 865 maybe disposed at any suitable location within the recirculation loop 835,e.g., downstream of or adjacent the supply header pressure sensor 860.

Referring to FIG. 9, the fluid dispensing system 215 may include acontroller 868, which may be a dedicated controller separate from themixture control system 405 (or the control system 400), or may be a partof the mixture control system 405 or may be controlled by the overallcontrol system 400). The controller 868 may be any suitable controller,such as a programmable linear controller. The controller 868 maycommunicate with one or more devices included in the fluid dispensingsystem 215 through data cables or a network 869, which may be a wired orwireless network. For example, the controller 868 may receive signals ordata (e.g., measurements) from at least one of the valve 865, pressuresensor 860, and/or the flow meter 855, and may send control signals tothese devices. For example, the controller 868 may receive pressure datafrom the pressure sensor 860 and send a control signal to the valve 865to adjust the position of the valve 865, based on the speed of the pump825, so as to maintain a substantially constant pressure (or backpressure) within the supply header region 836 and/or the recirculationloop 835 according to operating pressure set points received from thecontrol system 400. The controller 868 may implement any suitablecontrols, such as, for example, a feedback control, a feed forwardcontrol, or both, and may be responsive to set point or otherconfiguration signals received from the control system 400 to maintainthe substantially constant pressure (or back pressure). The controller868 may communicate with other devices included in the fluid dispensingsystem 215 as shown in FIG. 9 and FIG. 10, e.g., pre-filter pressuresensor 840, post-filter pressure sensor 850, etc.

Referring to FIG. 9, the fluid dispensing system 215 may include asecondary storage tank 870 configured to store fluid for refilling thestorage tank 820. The fluid dispensing system 215 may include a pump 880configured to pump fluid from the secondary storage tank 870 into thestorage tank 820. The pump 880 may be in fluidic communication with thesecondary storage tank 870 through a conduit 875, and with the storagetank 820 through another conduit 886. The secondary storage tank 870 maybe referred to as a refill tank, and the pump 880 may be referred to asa refill pump. In some embodiments, the refill pump 880 may be apneumatically operated pump. When the fluid level in the storage tank820 is below a predetermined level, the refill pump 880 may be energizedor activated to pump fluid from the secondary storage tank 870 to refillthe storage tank 820.

Referring to FIG. 9, the fluid dispensing system 215 may include a highlevel sensor 895, which may include a probe disposed within the storagetank 820 at an upper portion to measure a high level of the fluid withinthe storage tank 820. The fluid dispensing system 215 may also include alow level sensor 896, which may include a probe disposed within thestorage tank 820 at a lower portion to measure a low level of the fluidwithin the storage tank 820. In some embodiments, the fluid dispensingsystem 215 may not start initially unless the high level sensor 895indicates that the fluid level in the storage tank 820 is above apredetermined high level. In some embodiments, when the high levelsensor 895 in the storage tank 820 detects that the level of the fluidin the storage tank 820 is below the predetermined high level for aperiod of time (e.g., one minute, two minutes, etc.), the controller 868may energize or activate the refill pump 880 to refill the storage tank820 with fluid from the secondary storage tank 870 in response toreceiving the signal from the high level sensor 895.

In some embodiments, when the refill pump 880 is energized for more thana predetermined period of time (e.g., four minutes, five minutes, etc.)without receiving a signal from the high level sensor 895 indicatingthat the predetermined high level has been reached, the controller 868may initiate an alarm and may de-energize the refill pump 880. In someembodiments, when a signal received from the low level sensor 896indicates that the fluid level in the storage tank 820 is below apredetermined low level, the controller 868 may de-energize the systempump 825. The fluid dispensing system 215 may include a skid 890 forcontaining at least one of the storage tank 820, the system pump 825,the refill pump 880, and the secondary storage tank 870. Although notshown due to the limited space, the controller 868 may communicate withat least one of the high level sensor 895, the low level sensor 896, orthe refill pump 880 via cables or a network. The controller 868 mayreceive data or signals from at least one of the high level sensor 896,the low level sensor 896, or the refill pump 880, and may transmitcontrol signals to them to control their operations.

FIG. 10 shows an exemplary fluid dispensing system 215 for distributingfluid to multiple users (e.g., mixers, containers, etc.). As shown inFIG. 10, a plurality of distribution branches 901-905 may be connectedto the recirculation loop 835 at a supply header region 836. Althoughnot shown in FIG. 10 due to the limited space, the controller 868 shownin FIG. 9 may also be included in the fluid dispensing system 215 shownin FIG. 10, and may communicate with various devices or components viacables or wired or wireless networks (e.g., via the network 869). Eachdistribution branch 901-905 may include a flow meter 911-915. Eachdistribution branch 901-905 may include a proportional flow controlvalve 921-925. Each distribution branch 901-905 may include a discretecontrol valve 931-935. A plurality of users (e.g., mixers) 941-945 mayrequest different or the same amounts of fluid from the fluid dispensingsystem 215, and may receive precise amounts of fluid (e.g., doses)requested independently. The discrete control valves 931-935 may beon-off type control valves, which may provide a positive, drip-freecut-off.

Each of the flow meters 911-915 in the distribution branches may includea totalization function, which may count or calculate a total amount offluid that has been dispensed to a user. Each of the flow meters 911-915may transmit the measured flow rate during the dosing operation to aprogrammable linear controller, which may be separate from or includedin the controller 868. Each of the proportional flow control valves921-925 may be initially completely open (e.g., with 100% opening) andmay gradually close until the desired amount of fluid has been dispensedto the user. Alternatively or additionally, each of the proportionalflow control valves 921-925 may be programmed to include a high flowrate and a low flow rate. In a distribution branch (one of the braches901-905), when the total amount of fluid dispensed to a mixer hasreached the requested amount, the proportional flow control valve (e.g.,one of the valves 921-925) may close, and then the discrete controlvalve (e.g., one of the valves 931-935) may close.

Referring to FIGS. 9 and 10, the fluid dispensing system 215 may be usedfor a continuous skinning process. Additionally, the fluid dispensingsystem 215 may also be used for adding fluids (e.g., liquids) to producewet batch for extrusion, such as extrusion of ceramic articles. Thefluid dispensing system 215 may enable precise dosing of fluids tomultiple users (e.g., mixers) simultaneously without degrading accuracy.Steady flow and back pressure may be maintained within the recirculationloop 835, which includes the supply header region 836. The distributionbranches 901-905 may be controlled independently to dispense fluid toeach user without the need of coordinating sequences among the users.The fluid dispensing system 215 may be scaled based on the number ofusers. When additional users (e.g., mixers) need to be added to thefluid dispensing system 215, additional distribution branches may beadded to the recirculation loop 835 (e.g., the supply header region836). The recirculation design of the fluid dispensing system 215 mayprevent solids within the fluid from settling and being dispensed to theusers. The pump 825 may be programmed to pump fluids for recirculationduring periods of dosing (e.g., dispensing to the users) and afterextended periods of idleness.

Referring to FIGS. 9 and 10, in some embodiments, the supply headerpressure sensor 860 may provide pressure information to a compensatorlogic, which may be included in the controller 868. The pressureinformation from the supply header pressure sensor 860 may be used bythe controller 868 for controlling the proportional flow control valve865. The delivery system flow meter 855 may provide flow information toa programmable linear controller, which may be separate from or includedin the controller 868, via a suitable communication means, such aswireless or wired networks. The controller 868 may use the flowinformation to adjust the speed of the pump 825. The pump 825 may becontrolled by a variable frequency drive, which may be included in thecontroller 868. The flow rate within the recirculation loop 835 may beregulated by varying the speed of the pump 825. Pressure within therecirculation loop 835 may be controlled by adjusting the opening andclosing of the proportional flow control valve 865, which may regulateflow obtain the desired pressure. The fluid dispensing system 215 may beconfigured to provide a substantially consistent supply header pressureand sufficient fluid flow available to each user.

FIG. 11 shows a conventional fluid dispensing system 1000. As shown inFIG. 11, the conventional fluid dispensing system 1000 may include astorage tank 1003, a high level sensor 1004, a low level sensor 1005, apump 1006, a pre-filter pressure sensor 1008, a filter 1007, and adelivery line 1009. The conventional fluid dispensing system 1000 mayalso include a secondary storage tank 1001 and a refill pump 1002.Unlike the fluid dispensing system 215 described above with reference toFIG. 10, when multiple users (e.g., three users shown in FIG. 11)request fluids from the conventional dispensing system 1000, theconventional fluid dispensing system 1000 uses three individualdistribution branches 1011, 1012, and 1013 to dispense fluids. Eachindividual distribution branch may include a flow control valve (e.g.,one of the flow control valves 1014, 1015, and 1016). The conventionalfluid dispensing system 1000 does not include a recirculation loop. Inthe conventional system, the pump 1006 feeds multiple drops, and loss ofdispensing accuracy is common if dosed to more than one drop (e.g., morethan one user) at a time. The conventional system limits productionflexibility and fluid dispensing rate. In addition, without therecirculation loop, solids within the fluid to be dispensed may settleor be dispensed to the users.

FIG. 12 shows another conventional fluid dispensing system 1050. Asshown in FIG. 12, the conventional fluid dispensing system 1050 mayinclude a storage tank 1053, a high level sensor 1054, and a low levelsensor 1055. The conventional fluid dispensing system 105 may include asecondary storage tank 1051 and a refill pump 1052. When multiple users(e.g., three users) request fluids from the conventional fluiddispensing system 1050, individual distribution branches 1056, 1057, and1058 are set up for each of the users. Each distribution branch mayinclude an individual pump 1059, 1060, or 1061, an individual pre-filterpressure sensor 1062, 1063, or 1064, an individual filter 1065, 1066, or1067, and an individual delivery system flow meter 1068, 1069, or 1070.Each distribution branch may also include an individual flow controlvalve 1071, 1072, or 1073. Although the dispensing accuracy may beimproved as compared to the conventional system shown in FIG. 11, thisconventional fluid dispensing system 1050 may be costly due to theredundant components. In addition, without recirculation, solids withinthe fluid may settle or be dispensed to the users.

FIG. 13 shows components of an exemplary storage device 225 configuredto store a flowable mixture from the mixer 220. The storage device 225may be configured to store the flowable mixture during a continuousmixing and skinning process, or a batch-wise, index mode mixing andskinning process. In the event of downstream equipment stoppage, thestorage device 225 may allow the continuous mixing process to continuewithout stopping for a period of time (e.g., up to three hours). Inorder to handle periods of downstream equipment stoppage, the feed rateof flowable mixture entering into the storage device 225 may be reduced,and the flowable mixture that is forced into a downstream pump may bereduced.

The storage device 225 may have a shape suitable for ensuring properflow of the flowable mixture, such as a cone shape, although othershapes may also be used for the storage device 225. The storage device225 may be made of any suitable material, such as, for example, steel,stainless steel, etc. When a cone-shaped structure 1090 is used, theangle of the cone may be greater than 70 degrees. The storage device 225may be mounted on and supported by a frame 1100. The storage device 225may receive the flowable mixture from the mixer 220 through a receivingport or chute 1105, which may include a flanged opening. The capacity ofthe storage device 225 may be adjusted. For example, if more capacity isneeded, a straight section may be added above the cone-shaped structure1090, as shown in FIG. 7, to increase the storage volume.

The storage device 225 may include a cover 1110 that closes and sealsthe top opening of the cone-shaped structure 1090 to make the storagedevice 225 an enclosed vessel. The enclosed vessel may prevent theflowable mixture from drying out. The storage device 225 may include avacuum port 1115 disposed on the cover 1110 and connected to a vacuumsystem 1116. The vacuum system 1116 may be configured to apply a vacuumto the top portion of the storage device above the flowable mixture towithdraw or reduce air in an internal volume of the storage device abovethe flowable mixture, thereby reducing an amount of air being trapped inthe flowable mixture (e.g., de-airing the flowable mixture). The vacuumsystem 1116 may apply a vacuum of up to 15 inches of Hg. The vacuumsystem 1116 may prevent air from being trapped within the flowablemixture as the flowable mixture falls into the storage device 225 fromthe mixer 220. De-airing may increase the density of the flowablemixture, which may in turn improve the skin quality (e.g., by reducingthe defects such as pits and pocks) of the finished product. In someembodiments, the vacuum system 1116 may also be used to control (e.g.,increase or decrease) the density of the flowable mixture by controllingthe amount of air within the vessel available to be trapped within theflowable mixture.

The storage device 225 may include an auger 1120 disposed in the centerportion of the cone-shaped structure 1090, extending from the bottom ofthe cone-shaped structure 1090 to the tip portion of the cone-shapedstructure 1090. The auger 1120 may be connected to a servo or other typeof drive motor 1121 located adjacent the cover 1110. The motor 1121 maybe coupled to the auger 1120 so that the motor 1121 can cause the augerto rotate. The lower portion of the auger 1120 may include a helicalscrew blade 1125 configured to force the flowable mixture down to thepump 235 (not shown in FIG. 13) when the auger 1120 rotates. The pump235 may be located downstream of an outlet port or chute 1122 of thestorage device 225.

Referring to FIG. 13, the storage device 225 may include an externalvibration device 1130 configured to cause vibration in the storagedevice 225. Vibration may aid in the downward flow of the flowablemixture to the lower auger area where the helical screw blade 1125 islocated, helping to ensure that the flowable mixture can be forced tothe pump 235 by the helical screw blade 1125. The vibration device 1130may be mounted to an outer surface of the storage device 225. In someembodiments, the vibration device 1130 may be mounted to a rib 1135 thatmay run the length of the storage device 225 on the outer surface.

When a recirculation line 260 (shown in FIGS. 1 and 6) is included inthe mixture delivery system 200, the storage device 225 may include oneor more ports 1140 configured to receive recirculated flowable mixturefrom the recirculation line 260. The port 1140 may include a suitablefitting, such as a tri-clamp fitting that enables quick hose connectionswith the recirculation line 260.

The storage device 225 may also include one or more mounting structures1145 attached to the outer surface of the storage device 225 formounting on the frame 1100. The mounting structure 1145 may be disposedat an upper portion of the outer surface of the storage device 225. Themounting structures 1145 may be placed on one or more supportingportions 1150 of the frame 1100, such that the storage device 225 may besupported by the frame 1100.

The storage device 225 may include one or more load cells 1155configured to weigh the storage device 225 and/or the flowable mixturestored therein. In some embodiments, three load cells 1155 may be usedto weigh the storage device 225. The load cells 1155 may include atleast one summation box for providing a total amount of flowable mixturethat has been discharged from the storage device 225 based on changes inthe measured weight. The total amount of flowable mixture discharged maybe used by the control system 400 for weight inventory and processcontrol. In some embodiments, the load cells 1155 may be disposed on thesupporting portions 1150 where the mounting structures 1145 rest.Optional equipment may also included in the storage device 225, such aslevel sensors, probes, nozzles for quick cleaning without disassembly,additional ports for hose connections for incoming and/or outgoingflowable mixture.

FIG. 14A shows a top view of the storage device 225. FIG. 14B shows aside view of the storage device 225. FIG. 15 shows another side view ofthe storage device 225. The dimensions shown in FIGS. 13, 14A, 14B, and15 are for illustrative purposes, and dimensions of the storage device225 may differ from those shown in these figures in various embodiments.In some embodiments, the cone-shaped structure 1090 may have a height ofabout three feet, a diameter of about two feet at the opening covered bythe cover 1110, and a volume of about three cubic feet. The cone anglemay be about 72.5 degrees. The gearbox ratio may be about 70:1.

FIGS. 16A, 16B, and 17 show an exemplary auger 1120 suitable for use ina storage device 225. The auger 1120 may include a rod or shaft havingtwo segments with different diameters. The diameter of the upper segmentmay be greater than the diameter of the lower segment. The lower segmentmay be mounted with a helical screw blade 1125 extending from a tip end1160 to a middle portion of the auger 1120. The helical screw blade 1125may include a cone-shaped profile when rotating. The cone-shaped profileof the helical screw blade 1125 may closely match the cone shape formedby an inner wall of the cone-shaped structure 1090. In some embodiments,an angle 1165 formed by the profile and the shaft of the auger 1120 maybe about 16 degrees. In one embodiment, the angle 1165 may be 16.25degrees. The top line 1175 of the upside down triangle profile may beabout 10 inches. In one embodiment, the top line 1175 may be about 10.5inches. As shown in FIG. 16B, the height 1170 of the half revolutionfrom the tip end 160 may be about 1.1 inches. The diameter 1180 of thefirst half revolution from the tip end 160 may be about 1.8 inches.

FIG. 17 shows that an upper shaft 1185 of the auger 1120 may include adiameter 1190 of about 1.5 inches. A lower shaft 1195 of the auger 1120may include a diameter 1200 of about 0.75 inches. The first revolutionof the helical screw blade 1125 from the top may surround the uppershaft 1185. In the first revolution, the width 1205 of the blade 1125(e.g., ribbon) may be about 2 inches wide. The pitch 1210 of the firstrevolution from the top may be about 4 inches deep (e.g., a 4-inchpitch). The remaining evolutions of the helical screw blade 1125 mayinclude three revolutions surrounding the lower shaft 1195. The lowershaft 1195 may include a diameter of 0.75 inches. The pitch 1215 (e.g.,total height) of the three revolutions may be about 12 inches. Thedimensions described above and included in the figures are those of aparticular embodiment that exhibits improved performance in a conicalstorage device. However, an auger for use in a storage device 225 mayhave dimensions different from those shown in FIGS. 16B and 17 may beused for the auger 1120, for example, for handling different types ofmixtures.

The cone-shaped profile of the helical screw blade 1125 when it rotatesmay closely match the cone shape formed by the inner wall of thecone-shaped structure 1090. During a normal operation, when rotating,the outer periphery of the helical screw blade 1125 may be close to theinner wall of the cone-shaped structure 1090 without contacting theinner wall. Because of a tight clearance between the rotating helicalscrew blade 1125 and the inner wall of the cone-shaped structure 1090,the auger 1120 may force the flowable mixture down into the pump 235without introducing air bubbles into the flowable mixture, therebyimproving the density of the flowable mixture, which in turn may improvethe quality of the skin in the skinned articles.

FIG. 18 shows a control diagram for controlling the operations of themixture delivery system 200. The control diagram represents an exemplarycontrol scheme that may be implemented within the control system 400,such as within the mixture control system 405. The mixture controlsystem 405 may control the mixture delivery system 200 to provide aflowable mixture with a substantially consistent rheology to theskinning system 300, which in turn may result in improved skinningquality in the skinned articles. The mixture control system 405 mayaccount for the impact of variations in raw material properties (e.g.,particle size distribution or other properties) on the rheology of theflowable mixture.

In some embodiments, the mixture control system 405 may use a feedforward control to proactively account for the variations in theparticle size distribution. The mixture control system 405 may use acombination of feed forward and feedback controls to achieve defect freeor substantially defect free skinned articles. In some embodiments, thefeed forward control may detect variations in the particle sizedistribution of the dry material, and predict (estimate, calculate, ordetermine) the impact of the variation in the particle size distributionon the viscosity of the flowable mixture using a control model. Thefeedback control may include a first feedback control responsive to aninline viscometer (e.g., viscometer 296) that provides substantiallyconsistent and reliable information about the viscosity of the flowablemixture. The feedback control may use a second feedback controlresponsive to an inline densitometer (e.g., densitometer 295) thatprovides substantially consistent and reliable information about thedensity of the flowable mixture. In some embodiments, the feed forwardcontrol may use an adaptive model that may be updated (e.g., adapted) bythe overall control system 400 during operations using measuredviscosity and/or density to increase the model accuracy.

The mixture control system 405 may effectively control the viscosityand/or density of the flowable mixture using real-time or near real-timemeasurements of process parameters of the system 100. The overallcontrol system 400 may automatically adjust the set points (e.g., targetvalues) of the system parameters used by the mixture control system 405based on real-time or near real-time viscosity and/or densitymeasurements. The control schemes implemented by the mixture controlsystem 405 may be transferred to other product lines, where measures areavailable for detecting the raw material property variations, and/ordensity and/or viscosity of the flowable mixture. The control schemesimplemented by the mixture control system 405 may enable the skinningprocess to be performed by the skinning system 300 continuously withoutstopping to make changes to the set points (e.g., target values) of thesystem parameters. As a result, the system down time may be reduced, andmore consistent product quality may be provided. With improved qualityin the final skinned articles, material utilization rate may also beincreased.

Referring to FIG. 18, the control scheme implemented by the mixturecontrol system 405 may include a feed forward control 1300, and one ormore feedback controls. In some embodiments, the control scheme mayinclude a first feedback control 1305, a second feedback control 1310,and a third feedback control 1315. The feed forward control 1300 mayinclude a feed forward controller 1320. The particle size distributionmeasurement, which may be measured by the particle analyzer 205, may befed into the feed forward controller 1320 as input or disturbance.

FIG. 19 shows a sample particle size distribution of the dry material.The horizontal axis is the size of particle (unit: micron), and thevertical axis is the volume frequency percentage, which is the volumerepresented by particles of a certain size versus the total volume. Forexample, when the particle size distribution is continuously measured bythe particle analyzer 205, the feed forward controller 1320 maycontinuously receive the particle size distribution measurements fromthe particle analyzer 205 over time. The feed forward controller 1320may determine or calculate, using a control model, a variation in thereceived particle size distribution measurements over time. Based on thevariation in the measured particle size distribution, the feed forwardcontroller 1320 may determine (e.g., calculate, predict, or estimate) anadjustment to an amount of fluid to be added to the mixer 220, such as,for example, an amount of water (or “water call”).

Referring to FIG. 18, the first feedback control 1305 may include afirst feedback controller 1325. The first feedback controller 1325 mayreceive measured density (e.g., as measured by the densitometer 295) asa feedback. In some embodiments, the measured density may be filtered bya filter 1330 to remove noise, which may be a digital or analog signalfilter. The filter 1330 may be optional. The first feedback controller1325 may receive a density set point (or target value) as an input. Themeasured density (after being filtered or without being filtered) may becompared with the density set point to determine a difference in densityas indicated by a combination symbol 1331.

The first feedback controller 1325 may determine a mixer speed (orchange in mixer speed) that should be implemented based on the measureddensity and the density set point; for example, based on the differencebetween the measured density and the density set point. Alternatively oradditionally, the first feedback controller 1325 may determine ascrewfill ratio based on the measured density and the density set point.The determined mixer speed or screwfill ratio may be used to adjustoperations of the mixer 220. For example, the control system 400 maytransmit a control signal to the mixer 220 to adjust the mixer speed orthe screwfill ratio. Based o the control signal, the mixer 220 mayadjust at least one of the mixer speed or the screwfill ratio. AlthoughFIG. 18 only shows the mixer speed as an output of the first feedbackcontroller 1325, the mixer speed may be replaced with the screwfillratio.

Referring to FIG. 18, the second feedback control 1310 may include asecond feedback controller 1335. The second feedback controller 1335 maydetermine an amount of fluid to be added to the mixer 220 based onmeasured viscosity and the viscosity set point. In some embodiments, theviscosity may be measured by the viscometer 296. In some embodiments,the measured viscosity may be filtered by a filter 1340, or may not befiltered (i.e., the filter 1340 may be optional). The filter 1340 may bea digital or analog filter. The measured viscosity may be compared withthe viscosity set point, as indicated by a combination box 1332. Theamount of fluid determined by the second feedback controller 1335 may becombined with the adjustment to the amount of fluid determined by thefeed forward controller 1320, as indicated by a combination box 1333, toproduce a total amount of fluid to be added to the mixer 220. The amountof fluid to be added to the mixer 220 is represented by a “water call”signal in the control diagram in FIG. 18 and other control diagrams inthe subsequent figures. The “water call” signal may indicate not onlythe amount of water to be added to the mixer, but also an amount ofanother fluid, or a total amount of the water and another fluid to beadded to the mixer 220. The control system 400 may transmit a controlsignal indicating the total water call amount to the mixer 220. Based onthe control signal, the mixer 220 may adjust the water call amount. Forexample, the mixer 220 may send a request for the adjusted water callamount to the fluid dispensing system 215.

Referring to FIG. 18, the third feedback control 1315 may include athird feedback controller 1345 configure to control the return pressurewithin the recirculation line 260. The return pressure in therecirculation line 260 may be measured by the pressure sensor 265. Themeasured return pressure may be filtered by a filter 1350 or may not befiltered (i.e., the filter 1350 may be optional). The filter 1350 may bea digital or analog filter.

The third feedback controller 1345 may determine a pump speed of thepump 235 based on the measured return pressure and the return pressureset point. For example, the measured return pressure and the returnpressure set point may be compared, as indicated by the combinationsymbol 1355, and the third feedback controller 1345 may determine a pumpspeed of the pump 235 based on the difference between the measuredreturn pressure and the return pressure set point. The control system400 may transmit a control signal to the pump 235 to adjust the pumpspeed. The pump 235 may adjust the pump speed based on the controlsignal. The third feedback control 1315 may include a saturation box1360 configured to limit the pump speed to prevent the pump speed fromexceeding a predetermined range. Although not shown in the figures, insome embodiments, the return pressure may be replaced with the deliverypressure, and the return pressure set point may be replaced with thedelivery pressure set point. Thus, any discussions or illustrationsthroughout the present disclosure that involve return pressure (orreturn pressure set point) may be applicable to delivery pressure (ordelivery pressure set point). In the control scheme shown in FIG. 18,the mixer 220 may receive the dry material from the dry blend feeder805, which may be associated with one or more loss-in-weight load cellsconfigured provide information regarding the total amount of drymaterial that has been fed into the mixer 220.

Flowable Mixture Viscosity Controller Design

Feed Forward Model Development

In the example below, the amount of fluid to be added to the mixer 220is represented by the water call, and water is used as exemplary fluidthat is added to the mixer. The term water may also represent otherfluids, or a mixture of water and another fluid. The term water call mayalso represent an amount of a fluid other than water that is added tothe mixer 220, or a total amount of fluid (which may include a mixtureof water and another fluid) to be added to the mixer 220. In order todesign a feed forward controller (e.g., for feed forward controller1320), a model is developed. The model may be a gain matrix relationshipas seen equation (A-1).

Y=G*X  (A-1)

where G is the gain matrix, X is the particle size distribution (“PSD”)information, and Y is the model estimated viscosity. A sample particlesize distribution (PSD) for the dry material is shown in FIG. 19. ThePSD information is captured in sixty data points. The G matrix may befound using partial least square (“PLS”) regression. An experiment wasconducted to shift the PSD within the bounds of manufacturingspecification of the supply. The gain matrix was obtained using datafrom this experiment. The PLS regression model shows 78% correlationbetween PSD shifts/variations and the resulting viscosity variation with70% predictability.

The measurement of viscosity is affected by density, temperature, andpressure. Hence normalized viscosity as seen in equation (A-2) may beused.

V=Y/T/P/ρ  (A-2)

where Y is model estimated viscosity, T is temperature (F), P ispressure near the viscometer (psi), and ρ is density (g/mL).

An experiment was run in which water call was changed, with manipulatedvariable in the control system, to observe its effect on normalizedviscosity. The difference seen in the viscosity for the water callchange may be captured in another gain, G₁.

G ₁ =ΔV/ΔWC  (A-3)

where G₁ is the gain that defines the relationship between the changesseen in the normalized viscosity (ΔV) and the change in the water call(ΔWC). The normalized viscosity may be calculated from (ΔV)=V_(d)−V,where V_(d) is the desired normalized viscosity.

Controller Development

Feed Forward Control

The feed forward control scheme may use a proportional-only controller.Equation (A-4) represents a generalized expression for the feed forwardcontroller. Q_(D)(s) is the impact of particle size distribution (PSD)changes or variations on viscosity and may be obtained using the modeldescribed in equations (A-1)-(A-3). K_(P) is the proportional gain ofthe controller that may be obtained using the process dynamics betweenwater and viscosity.

U _(FF)(s)=K _(P) Q _(D)(s)  (A-4)

The feed forward controller calculations may be based on equations(A-1)-(A-3), where the PSD information X is transformed via gain matrixG to a predicted viscosity Y using the partial least squares (PLS)regression coefficients. The viscosity Y may be normalized bytemperature T, pressure P, and density p to obtain a normalizedviscosity V. The difference ΔV may be calculated by subtracting thepredicted normalized viscosity V from the desired normalized viscosity(V_(d)). The difference ΔV may be divided by G₁ obtained by equation(A-3) to determine the change in water call ΔWC needed to compensate forthe predicted viscosity change. After obtaining the needed change inwater call ΔWC, the total water call may be obtained by WC=WC_(ss)+ΔWC,where the WC_(ss) is the steady state water call.

FIG. 20 shows validation results of a feed forward controller modelimplemented in a control system such as illustrated in FIG. 18. Thestandard blend, blend A, and blend B were used to develop the model. Thenext three days were used to predict the viscosity. FIG. 20 compares theprediction with the actual measured viscosity. As shown in FIG. 20, thefeed forward controller model closely predicts the viscosity.

FIG. 21 shows feed forward controller validation results. As shown inFIG. 21, the feed forward controller was able to predict the adjustmentto the water call needed based on the PSD information within a 5% error.

One of the advantages of the feed forward control is that variations inviscosity due to PSD shifts and variations in raw materials can beproactively removed from the process without operator intervention,thereby saving time and materials. In addition, there is a benefit inmaximizing process consistency without placing high requirements on thesupplier specifications, thereby saving manufacturing costs.

An embodiment feed forward controller 1370 illustrated in FIG. 22 hasthe ability to adapt. As shown in FIG. 22, the control scheme forcontrolling the mixture delivery system 200 may include the adaptivefeed forward controller 1370. The adaptive feed forward controller 1370may include a model similar to that used by the feed forward controller1320 described above. In some embodiments, the adaptive feed forwardcontroller 1370 may replace the feed forward controller 1320 in thecontrol scheme shown in FIG. 18.

As shown in FIG. 22, the control scheme may include an adjustmentmechanism 1375 configured to adjust (or adapt) the feed forwardcontroller 1370 based on measured viscosity. The adjustment mechanismcan use any number of adaptive techniques, such as MRAC (model referenceadaptive control), gain scheduling, self-tuning, etc. As needed, newcontrol parameters for the feed forward controller may be communicatedusing the adjustment mechanism 1375. The PSD information (e.g., new PSDinformation) may be compared to the viscosity response of the system(e.g., measured viscosity), and the feed forward controller 1370 may beadjusted accordingly.

The adjustment mechanism 1375 may adjust a reference model 1380. Thefeed forward controller 1370 may be adjusted based on the referencemodel 1380. The reference model 1380 may determine a reference viscositybased on a measured viscosity and the particle size distribution. Thereference viscosity determined by the reference model may be input intothe adjustment mechanism 1375. In addition, the output of the feedforward controller 1370, i.e., the adjustment to the amount of fluid tobe added to the mixer 220 (e.g., changes to the water call) may be inputinto the adjustment mechanism 1375 as a parameter. The adjustmentmechanism 1375 may adjust the feed forward controller 1370 based on themeasured viscosity, the reference viscosity, and the output from thefeed forward controller 1370. In other words, the feed forwardcontroller 1370 may determine the adjustment to the amount of fluid tobe added to the mixer 220 based on both the PSD information and themeasured viscosity.

Referring to FIG. 22, the control scheme may also include a feedbackcontrol 1385, which may include a feedback controller 1390. The feedbackcontroller 1390 may determine an amount of fluid to be added to themixer 220 (e.g., “water call”) based on the measured viscosity and theviscosity set point. The amount of fluid determined by the feedbackcontroller 1390 may be combined with the adjustment to the amount offluid determined by the feed forward controller 1370 to obtain the totalamount of fluid to be added to the mixer 220. The control system 400 maytransmit a control signal to the mixer 220 with the total amount offluid information. Based on the control signal, the mixer 220 may adjustthe total amount of fluid (e.g., water call) to be requested from thefluid dispensing system 215.

Referring to FIGS. 18 and 21, the feedback control designs are discussedbelow. For discussion purposes, the amount of fluid to be added to themixer 220 is represented by the water call, although the feedbackcontrol designs are applicable to other types of fluids.

Feedback Control

The feed forward control scheme discussed above is able to controlproactively the viscosity by predicting the impact of the disturbance(e.g., variations in the PSD) before it affects the process. Feedbackcontrol may be able to provide stability and robustness to the overallcontrol scheme. Feedback control may provide a means of self-regulatingthe viscosity. Depending on the control parameters, a feedback loop maycompensate for disturbances. However, there may be loss of flowablemixture by the time the water call adjusts to disturbances iteratively.

The normalized viscosity measurement will be first filtered so that thefeedback controller does not respond to noise. An exemplary filter maybe represented by equation (A-5):

Viscosity(k)=α×Viscosity(k)+(1−α)×Viscosity(k−1)  (A-5)

where k is the sample time and α is the filter parameter. Since this isa first order filter, the smaller the a value, the more the signal willbe filtered. Smaller a value may induce a time delay in the filteredsignal. Choosing an appropriate α value would achieve a balance betweenthe amount of filtering and time delay.

The filtered viscosity may be compared with the target viscosity (e.g.,viscosity set point) as determined by the operator or skinning processcontrol loops, and the error may be sent to the feedback controller,which may automatically adjust the water call percentage to reduce theerror. An example of the structure of the feedback controller (e.g.,feedback controller 1335) may be:

U _(FB) ¹(s)=G ₂ ⁻¹(s)F ₁(s)  (A-6)

where, U_(FB) ^(I)(s) is the output of the feedback controller inLaplace form, F₁(s) is the Laplace transform representation of a lowpass filter and G₂ ⁻¹(s) is the inverse of the Laplace transformrepresentation of the process model between the water call andviscosity. One form of the process model may be:

G ₂(s)=K ₁ e ^(−θ) ¹ ^(s)/(1+τ₁ s)  (A-7)

where K₁, θ₁, τ₁ are the process gain, time delay, and the time constantrespectively describing the relationship between the water call and theviscosity. The process model is a function of the flowable mixturecomposition and process design such as the length of tubing from themixer 220 to the location of the viscometer 296, the type of tubingused, etc.

An example form of the feedback controller may be:

U _(FB) ^(I)(s)=K _(P) ^(I) +K _(I) ^(I) /s  (A-8)

where, K_(P) ^(I) and K_(I) ^(I) are the proportional and integral gainfor the feedback controller. The output of the feedback controller iscombined with the output of the feed forward controller to obtain thefinal controller output, which may be defined as:

U(s)=U _(FB) ^(I)(s)−U _(FF)(s)  (A-9)

Flowable Mixture Density Controller Design

The measured density (as measured by, e.g., an inline densitometer 295)may be first filtered so that the feedback controller does not respondto noise. An exemplary filter may implement a calculation such as inequation (A-10):

Density(k)=α×Density(k)+(1−α)×Density(k−1)  (A-10)

where k is the sample time and a is the filter parameter. As mentionedearlier in equation (A-5), there is a trade-off in choosing the filterparameter between a time delay and the amount of filtering.

The filtered density may be compared with the target density asdetermined by the operator or skinning process control loops, and theerror may be sent to the density feedback controller (e.g., feedbackcontroller 1325 shown in FIG. 18), which may automatically adjust thespeed of the mixer 220 (or the screwfill ratio of the mixer 220) toreduce the error. The structure of the feedback controller (e.g.,feedback controller 1325) may be:

U _(DM) ^(I)(s)=G ₃ ⁻¹(s)F ₂(s)  (A-11)

where U_(DM) ^(I)(s) is the output of the feedback controller in Laplaceform, F₂(s) is the Laplace transform representation of a low passfilter, and G₃ ⁻¹(s) is the inverse of the Laplace transformrepresentation of the process model between the water call andviscosity. One form of the process model may be:

G ₃(s)=K ₂ e ^(−θ) ² ^(s)/(1+τ₂ s)  (A-12)

where, K₂, θ₂, τ₂ are the process gain, time delay, and the timeconstant respectively describing the relationship between the mixer rpm(e.g., speed of the mixer) and the density. The process model may be afunction of the flowable mixture composition and batch process designs(e.g., mixture delivery system designs), such as the length of tubingfrom the mixer 220 to the location of the densitometer 295, the type oftubing used, etc. Example data that may be used to determine theparameters for the model used in FIGS. 23A and 23B are K₂=−0.00125 g/mLper rpm, θ₂=8 minutes, and τ₂=7.875 minutes.

FIGS. 23A and 23B show the density model validation results. FIG. 23Ashows the model density and the actual measured density. The dashed lineshows the model density, and the solid line shows the measured densityof the flowable mixture. As shown in FIG. 23A, the measured densitymatches the model density closely. FIG. 23B shows the speed (rpm) of themixer 220, which was adjusted to control the density. Two step tests onthe mixer 220 were used to develop the model.

An example form of density feedback controller (e.g., feedbackcontroller 1325) may be:

U _(DM) ^(I)(s)=K _(P) ^(II) +K _(I) ^(II) /s  (A-13)

where K_(P) ^(II) and K_(I) ^(II) are the proportional and integral gainfor the density feedback controller.

FIGS. 24A and 24B show the density controller validation results. FIG.24A shows the modeled density and the measured density. The solid lineshows the model density and the dashed line shows the measured density.As shown in FIG. 24A, the measured density tracks the modeled density inabout twenty minutes. FIG. 24B shows the speed (rpm) of the mixer 220,which is adjusted to control the density. The controller used is aproportional integral feedback controller which controls the mixer 220.FIGS. 24A and 24B show that the controller responds to a request tochange the density.

FIG. 25 is a flowchart showing an exemplary method 1400 for controllingthe mixture delivery system 200. The method 1400 may include measuring aparticle size distribution of a dry material (block 1405). Themeasurement may be performed by the particle analyzer 205 shown in FIGS.1 and 6. The method 1400 may include mixing the dry material and a fluidin a mixer (e.g., mixer 220) to produce a flowable mixture (block 1410).The method 1400 may include pumping (e.g., by the pump 235) the flowablemixture to a delivery line (e.g., the delivery line 240) (block 1415).The method 1400 may include measuring at least one of a density or aviscosity of the flowable mixture (block 1420). The measurement of thedensity may be performed by the in-line densitometer 295 shown in FIG.6. The measurement of the viscosity may be performed by the in-lineviscometer 296 shown in FIG. 6.

The method 1400 may include determining, using a feed forward controller(e.g., the feed forward controller 1320 shown in FIG. 18), an adjustmentto an amount of the fluid (e.g., water call) to be added to the mixer220 based on a variation in the measured particle size distribution(block 1425). The method 1400 may include determining, using at leastone feedback controller (e.g., the first feedback controller 1325 and/orthe second feedback controller 1335 shown in FIG. 18), at least one of ascrewfill ratio (or alternatively, the mixer speed) of the mixer or theamount of the fluid to be added to the mixer based on at least one ofthe measured density or the measured viscosity (block 1430). The method1400 may include transmitting a control signal to the mixer 220 toadjust at least one of the amount of the fluid to be added to the mixer220 or the screwfill ratio (or mixer speed) of the mixer 220, based onan output of at least one of the feed forward controller (e.g., the feedforward controller 1320) or the at least one feedback controller (e.g.,the first feedback controller 1325 and/or the second feedback controller1335) (block 1435).

Skinning System and Controls

FIG. 26 is an isometric view of the skinning system 300 in accordancewith an embodiment. The skinning system 300 may include the manifold ormanifold assembly 305 and the skinning pipe 310. The manifold 305 may beconfigured to receive a flowable mixture from the mixture deliverysystem 200, and deliver the flowable mixture to the skinning pipe 310.In some embodiments, the manifold 305 may provide support to theskinning pipe 310. In some embodiments, the manifold 305 may include ahole at a center portion, and the skinning pipe 310 may be mounted tothe manifold 305 within the hole. The manifold 305 may supply flowablemixture to the skinning pipe 310 through distribution grooves (shown inFIG. 36). In some embodiments, the skinning pipe 310 may not be mountedto the manifold 305, but instead, be mounted to a dedicated mountingdevice connected to a frame structure of the skinning system 300. Themanifold 305 may be mounted on a frame structure 1500, for example,through one or more mounting brackets 1505. The mounting bracket 1505may be mounted to the frame structure 1500 using suitable fasteningmeans, such as screws, bolts, nuts, etc.

The skinning pipe 310 may include an inner space. In some embodiments,the inner space may be defined by a curved circumferential wall of theskinning pipe 310. Although the skinning pipe 310 is shown to have acircular cross section, it may have any other suitable cross sectionshape defined by the shape of the articles to be skinned, including, forexample, square, ellipse, rectangle, triangle, polygon, etc. Theskinning pipe 310 may receive an article (e.g., an unskinned article),which may move axially along the inner space of the skinning pipe 310.While the article moves axially along the inner space, the skinning pipe310 may apply (or coat) the flowable mixture to an outer surface of thearticle. An unskinned article may enter the skinning pipe 310 from aninlet (e.g., the lower open end of the skinning pipe 310), and move outof the skinning pipe 310 from an outlet (e.g., the upper open end of theskinning pipe 310) as a skinned article with flowable mixture applied onits outer surface.

Referring to FIG. 26, the skinning system 300 may include the articlefeeding mechanism 315. The article feeding mechanism 315 may be mountedto the frame structure 1500. The article feeding mechanism 315 may belocated below the manifold 305 and the skinning pipe 310 in a verticaldirection. The article feeding mechanism 315 may be configured tosupport an article, center and/or align the article with the inner spaceof the skinning pipe 310. The article feeding mechanism 310 may beconfigured to push the article into the inner space of the skinning pipe310 from the inlet of the skinning pipe 310.

Referring to FIG. 26, the article feeding mechanism 315 may include acentering mechanism 1510 and a platen 1515. The platen 1515 may beconfigured to support an article (e.g., an unskinned article). Thecentering mechanism 1510 may include a plurality of centering devices1520 surrounding the platen 1515. For illustrative purposes, fourcentering devices 1520 are shown in FIG. 26, although the centeringmechanism 1510 may include any other number of centering devices 1520,such as, for example, two, three, six, etc. With the unskinned articleresting on the platen 1515, the centering devices 1520 may be activatedto center the unskinned article in order to align the unskinned articlewith the inner space of the skinning pipe 310, before or when theunskinned article is pushed into the skinning pipe 310.

The article feeding mechanism 315 may include any other suitablemechanisms for pushing the unskinned articles into the skinning pipe310, and/or aligning the unskinned articles with the skinning pipe 310.For example, in some embodiments, the article feeding mechanism 315 mayinclude a platen disposed at the bottom of one or more articles, and acentering pipe that is not disposed around the platen, but above theplaten in the middle way between the skinning pipe and the platen. Theplaten may be moved up and down relative to the centering pipe, whichmay be fixed at a position relative to the skinning pipe. The centeringpipe may include a pipe configured to center and/or align the articlespushed by the platen, before the articles are pushed into the skinningpipe. The centering pipe may not move together with the platen.

In some embodiments, the article feeding mechanism 315 may include oneor more transfer arms each having a tooth type element (e.g., a rod or anut) configured to engage with a cavity of a plate disposed at a bottomsurface of each article to hold and support the articles. The transferarms pick up the articles at a position below the skinning pipe 310, andpushes the articles into the skinning pipe 310 using the plate and thetooth type element.

In some embodiments, the article feeding mechanism 315 may include arobotic arm configured to support the article at the bottom of thearticle, and pushes the article upward into the skinning pipe 310. Insome embodiments, the article feeding mechanism 315 may include one ormore rollers disposed around the outer surfaces of the articles forpushing the articles into the skinning pipe using frictional forcesbetween the rollers and the outer surfaces of the articles. In someembodiments, the rollers may include pins or mechanical fingers that mayengage with the outer surfaces of the articles while pushing thearticles into the skinning pipe 310. In some embodiments, the articlefeeding mechanism 315 may include a long pipe disposed between theskinning pipe 310 and a position where unskinned articles are to beloaded into the long pipe. The article feeding mechanism 315 may includea platen configured to push a plurality of articles stacked within thelong pipe into the skinning pipe 310. The long pipe may be aligned withthe skinning pipe 310.

Referring to FIG. 26, the skinning system 300 may include a lowercarriage 1525 located below the article feeding mechanism 315 andconfigured to support the article feeding mechanism 315. The lowercarriage 1525 may be mounted to the frame structure 1500. The framestructure 1500 may include a rail or track 1530 disposed in the verticaldirection. The rail 1530 may be a vertical rail. The lower carriage 1525may be mounted on the rail 1530 and may be movable along (e.g., up anddown) the rail 1530 in the vertical direction relative to the skinningpipe 310. As the lower carriage 1525 moves along the rail 1530, thearticle feeding mechanism 315 may be moved upward toward the manifold305 (and the skinning pipe 310) and downward away from the manifold 305(and the skinning pipe 310).

As the article feeding mechanism 315 moves upward toward the manifold350 (and the skinning pipe 310), the unskinned article disposed on theplaten 1515 may be pushed into the inner space of the skinning pipe 310to receive the flowable mixture during the skinning process. At acertain position or elevation of the article within the skinning pipe310, or in response to the vacuum system 320 acquiring the article, thearticle feeding mechanism 315 may stop pushing the article and may movedownward to receive another unskinned article. The skinning system 300may include a lower servo motor 1535 configured to move the lowercarriage 1525 (and hence the article feeding mechanism 315) along therail 1530. The lower servo motor 1535 may be mounted to the framestructure 1500 at a lower end of the rail 1530, as shown in FIG. 26,although it may be located at any other suitable location.

Referring to FIG. 26, the skinning system 300 may include an uppercarriage 1540. The upper carriage 1540 may be mounted on the rail 1530at a top portion above the manifold 305. The upper carriage 1540 maysupport the vacuum system 320. The vacuum system 320 may be mounted tothe upper carriage 1540. The upper carriage 1540 may move along (e.g.,up and down) the rail 1530 to move the vacuum system 320 relative to themanifold 305 (and the skinning pipe 310). The skinning system mayinclude an upper servo motor 1545 configured to move the upper carriage1540 (and hence the vacuum system 320). The upper servo motor 1545 maybe mounted to the frame structure 1500 at an upper end of the rail 1530,as shown in FIG. 26, although it may be located at any other suitablelocation.

Referring to FIG. 26, the vacuum system 320 may include a vacuum chuck1550. The vacuum chuck 1550 may be mounted to the upper carriage 1540.The vacuum chuck 1550 may be configured to be in contact with a surfaceof an article (e.g., an at least partially skinned article), while thearticle moves axially along the inner space of the skinning pipe 310 toreceive the flowable mixture. Through the vacuum chuck 1550, the vacuumsystem 320 may apply a vacuum to the at least partially skinned articleto create a vacuum force that enables the vacuum chuck 1550 to hold thearticle. The vacuum chuck 1550 may pull the article out of the skinningpipe 310 as the article moves axially along the inner space of theskinning pipe 310 to receive the flowable mixture. The vacuum chuck 1550may be made of one or more suitable materials, such as, for example,rubber, steel, stainless steel, aluminum, copper, ceramic, etc.

Referring to FIG. 26, the skinning system 300 may include at least onelaser device 1555 (e.g., at least one second laser device 1555) disposedadjacent an outlet (e.g., the upper opening) of the skinning pipe 310.The at least one laser device 1555 may be configured to monitor and/ordetect presence of a defect (e.g., pits, pocks, fast flow, starvation)on the skinned article (e.g., on the skin). Thus, the at least one laserdevice 1555 may be referred to as at least one defect measuring laserdevice 1555. In some embodiments, the at least one laser device 1555 maybe mounted on the manifold 305 or the mounting bracket 1505. The laserdevice 1555 may be mounted to other portions of the skinning system 300,such as, for example, a dedicated mounting frame attached to the framestructure 1500. FIG. 26 shows four laser devices 1555. Any othersuitable number of laser devices may be used, such as, for example, one,two, three, five, six, etc.

The control system 400 may be configured to determine a type of thedefect detected from the skin based on signals or data received from theat least one laser device 1555. For example, different types of defects(e.g., fast flow defects, starvation defects, pit defects, pock defects,ring defects) may be associated with different signals having differentcharacteristics (e.g., magnitudes, frequencies, pixel characteristics).The control system 400 may extract information from the signals or datareceived from the at least one laser device 1555 and determine the typeof defect based on the extract information. Alternatively, the at leastone laser device 1555 may detect the type of defect on the skin.

In some embodiments, the at least one laser device 1555 disposedadjacent the outlet of the skinning pipe 310 may also be configured tomeasure dimensions (e.g., diameter, radius, circumference, axial length,and/or outer peripheral length) of the skinned articles. In someembodiments, the at least one laser device 1555 may include a firstplurality of laser devices configured to measure dimensions (e.g.,diameter, radius, circumference, axial length, and/or outer peripherallength) of the skinned articles, and a second plurality of laser devicesconfigured to monitor and/or detect the defects on the skinned articles.For example, FIG. 26 shows four laser devices 1555. Two laser devices1555 may be used for monitoring and/or detecting the defects, and theother two laser devices 1555 may be used for measuring the dimensions(e.g., diameter, radius, circumference, axial length, and/or outerperipheral length) of the skinned articles. Also, more laser devices1555 may be included. For example, eight laser devices 1555 may bedisposed adjacent the outlet of the skinning pipe 310, four formonitoring and/or detecting the defects, and four for measuring thedimensions (e.g., diameter, radius, circumference, axial length, and/orouter peripheral length) of the skinned articles.

Referring to FIG. 26, the skinning system 300 may include at least onelaser device 1560 disposed adjacent an inlet (e.g., the lower opening)of the skinning pipe 310. The at least one laser device 1560 may beconfigured to measure a dimension (e.g., diameter, radius,circumference, axial length, and/or outer peripheral length) of anunskinned article. Thus, the at least one laser device 1560 may bereferred to as at least one dimension measuring laser device 1560. Insome embodiments, the at least one laser device 1560 may be mounted onthe manifold 305 or the mounting bracket 1505. The laser device 1560 maybe mounted to other portions of the skinning system 300, such as, forexample, a dedicated mounting frame attached to the frame structure1500. FIG. 26 shows four laser devices 1560. Any other suitable numberof laser devices may be used, such as, for example, one, two, three,five, six, etc.

In some embodiments, when the at least one laser device 1555 isconfigured to measure a dimension (e.g., diameter, radius,circumference, axial length, and/or outer peripheral length) of theskinned article, the dimension of the skinned article measured by thelaser device 1555 and the dimension of the unskinned article measured bythe laser device 1560 may be used to determine, e.g., by the controlsystem 400, the thickness of the skin. The laser devices 1555 and 1560may transmit data or signals about the measured dimensions of theunskinned articles and the skinned articles to the control system 400.The control system 400 may compare the dimensions of the unskinnedarticle as measured by the laser device 1560 with the dimensions of thecorresponding skinned article as measured by the laser device 1555 tocalculate the thickness of the skin. For example, the control system 400may subtract a diameter of the unskinned article from a diameter of thecorresponding skinned article to obtain the thickness of the skin (e.g.,flowable mixture). The skin thickness information may be used by thecontrol system 400 to control the mixture delivery to the manifold 305(e.g., adjusting the amount and/or the pressure of mixture delivered tothe manifold 305), and/or the skinning system (e.g., the centeringmechanism 1510).

Referring to FIG. 26, the skinning system 300 may include at least onerobot or robotic arm configured to load or unload an article. Forexample, the skinning system 300 may include two robots, a loading robot1565 configured to load unskinned articles to the article feedingmechanism 315, and an unloading robot 1566 configured to unload skinnedarticles from the vacuum chuck 1550. The unloading robot 1566 mayinclude one or more arms 1570 for grabbing (or supporting) and unloadinga skinned article received from the vacuum chuck 1550. The arms 1570 maybe adjustable to fit articles of different sizes (e.g., differentdiameters, different radii, different circumferences, and/or differentouter peripheral lengths).

The loading robot 1565 may include a vacuum chuck 1571 configured tograb or hold an unskinned article using vacuum force or vacuum pressure.While the vacuum chuck 1571 holds the unskinned article, the loadingrobot 1565 may lift and transport the unskinned article to the articlefeeding mechanism 315. The unskinned article may include a spacer (notshown in FIG. 26) located at its bottom surface to aid in creating avacuum within the body of the unskinned article. The vacuum chuck 1571of the loading robot 1565 may be similar to the vacuum chuck 1550mounted to the upper carriage 1540, or may be different.

FIGS. 27A-27E schematically show the operations of the skinning system300. FIG. 27A shows that at a certain stage, the article feedingmechanism 315 may support an unskinned article 1581 on the platen 1515,while pushing the unskinned article 1581 into the skinning pipe 310. Atthe same time, there may be an article 1582 on top of the article 1581moving inside the inner space of the skinning pipe 310 to receive theflowable mixture, and an article 1583 on top of the article 1582, whichmay have been skinned or at least partially skinned. Although FIGS.27A-27E shows that the article feeding mechanism 315 and the vacuumsystem 320 (which includes the vacuum chuck 1550) may simultaneouslytransfer (e.g., by pushing and pulling), the skinning system 300 maytransfer any suitable number of articles, such as, for example, one,two, four, five, six, etc. In addition, the skinning system 300 may beconfigured to skin articles having the same length or different lengths.For example, the skinning system 300 may be configured to skin a firstgroup of articles with a first length, and a second group of articleswith a second length different from the first length. Articles withdifferent lengths may be mixed. For example, the first article to beskinned may have a first length, and a second article to be skinned mayhave a second length different from the first length, and a thirdarticle to be skinned may have a third length different from the firstlength and/or the second length.

Referring to FIGS. 27A-27E, the vacuum chuck 1550 may include one ormore vacuum zones. In the example shown in FIG. 27A, the vacuum chuck1550 may include two vacuum zones 1590 and 1595, a center (or inner)vacuum zone 1590 in the center, and a side (or outer) vacuum zone 1595on the sides surrounding the center vacuum zone 1590. The center vacuumzone 1590 and the side vacuum zone 1595 may be controlled (e.g.,activated or deactivated) independently. In some embodiments, the centervacuum zone 1590 may extend through more than one articles (e.g., twoarticles 1583 and 1582), and the side vacuum zone 1595 may extend onlywithin one article (e.g., article 1583). In some embodiments, the centervacuum zone 1590 may extend within one article, and the side vacuum zone1595 may extend through more than one article (e.g., two or morearticles).

Referring to FIGS. 27A-27F, spacers may be disposed at the bottomsurface of an article to aid in creating and maintaining the vacuumforce or vacuum pressure within the vacuum zones 1590 and 1595 bysealing the air flow at the bottom surface of the article. With thespacers located at the bottom surfaces of the articles, high vacuumpressure may be generated within the bodies of the articles using thevacuum system 320, enabling the vacuum chuck 1550 to hold and pull oneor more articles while the articles move along the inner space of theskinning pipe 310.

The vacuum chuck 1550 may hold an article at the top surface of thearticle. The high vacuum pressure generated within the articles mayensure that the top surface of the article is securely attached to thevacuum chuck 1550 even when the article is experiencing external forces,such as gravity and the frictional forces exerted on the article whenthe article is being applied with the wet, flowable mixture through theskinning pipe 310. Depending on the number of vacuum zones used in thevacuum system 320, or the number of articles the vacuum chuck 1550 isdesigned to hold/pull together, the spacers disposed at the bottomsurfaces of articles may have the same shape or different shapes. Forexample, when the vacuum chuck 1550 is designed to hold/pull one articleat a time, a circular plate shaped spacer may be disposed at the bottomsurfaces of the articles. When the vacuum chuck 1550 is designed tohold/pull two articles at a time, different shapes of spacers may bedisposed alternately at the bottom surfaces of the articles.

For example, the spacers may include two shapes complementing each othersuch that when used together, the two spacers disposed at the two bottomsurfaces of two articles may cover the entire or substantially theentire area of the cross section of the bottom surfaces. In other words,the total area covered by the two spacers may equal to or substantiallyequal to the area of the bottom surface of an article. The shapes of thespacers may depend on the shape of the bottom surface of the articles.For example, when cylindrical articles 1581, 1582, and 1583 are to beskinned, donut shaped spacers 1600 and donut hole shaped spacers 1605may be alternately disposed at the bottom surfaces of the articles toseal off the multiple vacuum zones 1590 and 1595. For example, a donutshaped spacer 1600 (a first spacer) may be disposed at the bottomsurface of the article 1583 to seal off the vacuum zone 1595 (a firstvacuum zone), a donut hole shaped spacer 1605 (a second spacer) may bedisposed at the bottom surface of the article 1582 to seal off thevacuum zone 1590 (a second vacuum zone), a donut shaped spacer 1600 maybe disposed at the bottom surface of the article 1581, which may sealoff another vacuum zone 1590 when it is generated, and so forth.

As shown in FIGS. 27A-27F, when articles 1581, 1582, and 1583 arestacked, the donut shaped spacer 1600 is disposed between the articles1582 and 1583, and the donut hole shaped spacer 1605 is disposed betweenthe articles 1582 and 1581. The sequence of the spacers may be changed.For example, a donut hole shaped spacer 1605 may be disposed at thebottom surface of the articles 1583 and 1581, and a donut shaped spacer1600 may be disposed at the bottom surface of the article 1582. Thedonut shaped spacer 1600 and the donut hole shaped spacer 1605complement each other to cover an area equal to or substantially equalto the area of the a bottom surface of one of the articles 1583 and1582, such that the vacuum force or vacuum pressure may be generated andmaintained within both vacuum zones 1590 and 1595.

As shown in FIG. 27A, both vacuum zones 1590 and 1595 may be generatedsuch that the vacuum chuck 1550 may hold the article 1583 and pull notonly the article 1583 but also the article 1582 with the vacuum force.Different number of vacuum zones may be used along with different shapesof spacers such that the vacuum chuck 1550 may hold and pull more thantwo articles at a time or only one article at a time. The spacers 1600and 1605 may be made of any suitable material, such as paper, mylarplastic, etc. In the stage shown in FIG. 27A, the vacuum system 320 ispulling the article 1583 while the article feeding mechanism 315 ispushing the articles 1581, 1582, and 1583 together. In other words, atthis stage, the upper carriage 1540 is pulling up the articles, and atthe same time, the lower carriage 1525 is pushing the articles up. Boththe upper carriage 1540 and the lower carriage 1525 may move togetherupward at the same speed.

Referring to FIG. 27B, the vacuum chuck 1550 holds and pulls the skinnedarticle 1583 out of the skinning pipe 310 by moving upward in thevertical direction away from the skinning pipe 310. Before or after theskinned article 1583 moves out of the skinning pipe 310, the centervacuum zone 1590 may be deactivated so that no or little vacuum force isapplied to the article 1582. The timing of deactivation may bedetermined based on a force experienced by the upper carriage 1540.Without the vacuum applied to the article 1582, the article 1583 maydisengage from the article 1582 and be moved away from the article 1582.

In some embodiments, the center vacuum zone 1590 (or the side vacuumzone 1595, depending on the type of spacer attached to the bottom ofarticle 1583) may be deactivated after the article 1583 has been pulledout of the skinning pipe 310, and while the vacuum chuck 1550 and thearticle feeding mechanism 315 are moving at substantially the samespeed. This stage shown in FIG. 27B may be referred to as a hand-offstage. The timing of the hand-off may be determined based on forcesbetween the vacuum chuck 1550 (or the upper carriage 1540) and thearticle feeding mechanism 315 (or the lower carriage 1525). For example,the timing of activating or deactivating one or more of the vacuum zones1590 and 1595 may be determined by the control system 400 based on theforces between the vacuum chuck 1550 (or the upper carriage 1540) andthe article feeding mechanism 315 (or the lower carriage 1525). Afterthe center vacuum zone 1590 is deactivated, the upper carriage 1540 (towhich the vacuum chuck 1550 is mounted) may move upward at a greaterspeed than the lower carriage 1525, thereby moving the skinned article1583 away from the article 1582. In the meantime, the article feedingmechanism 315 may continue to push the articles 1581 and 1582 throughthe skinning pipe 310 from the bottom.

After the vacuum chuck 1550 moves up to a certain position at whichpoint the article is clear of the skinning pipe 310 and accessible forremoval, the unloading robot 1566 (see FIG. 26) may remove the skinnedarticle 1583 along with its spacer from the vacuum chuck 1550. Thevacuum chuck 1550 may be deactivated to stop generating the vacuumpressure within the article 1583, or be controlled to reduce the vacuumpressure within the article 1583. The article 1583, along with itsspacer, may drop from the vacuum chuck 1550 and be caught by the arms1570 of the unloading robot 1566. In some embodiments, the vacuum chuck1550 may place the article 1583 with its spacer onto the arms 1570 ofthe unloading robot 1566, and then reduce or stop the vacuum pressuregenerated within the article 1583. As shown in FIG. 27C, after theskinned article 1583 has been removed from the vacuum chuck 1550, thevacuum chuck 1550 (through the motion of the upper carrier 1540) maymove down toward the skinning pipe 310 while the article feedingmechanism 315 continues to push the articles 1581 and 1582 through theskinning pipe 310.

As shown in FIG. 27D, after the vacuum chuck 1550 moves to a positionclose to the article 1582, the vacuum chuck 1550 may be stopped (e.g.,under control of the skinning control system 410). The vacuum chuck 1550may wait for the article 1582 to contact (e.g., touch) the vacuum chuck1550. After the vacuum chuck 1550 contacts the article 1582, the centervacuum zone 1590 and/or the side vacuum zone 1595 may be activated.Vacuum force or vacuum pressure may be applied to both the articles 1581and 1582, enabling the vacuum chuck 1550 to hold and pull the articles1581 and 1582 together upward to move through the skinning pipe 310.

Although not shown in FIG. 27D, there may be a stage (i.e., a period oftime) when the vacuum system 320 (or the upper carriage 1540) and thearticle feeding mechanism 315 (or the lower carriage 1525) move togetherupward at the same speed. While they move together at the same speed,the article feeding mechanism 315 (or the lower carriage 1525) may stopmoving upward, and start retrieving downward, leaving the vacuum system320 (or the upper carriage 1540) pulling both articles alone. This mayalso be referred to as a hand-off stage. The article feeding mechanism315 may move downward to a position to receive another unskinnedarticle, as shown in FIG. 27E. The loading robot 1565 may place theunskinned article onto the article feeding mechanism 315. For example,the loading robot 1565 may hold the unskinned article by vacuumpressure, lift it, and place it onto the paten 1515 of the articlefeeding mechanism 315.

The process or cycle shown in FIGS. 27A-27E may be repeated until theskinning process is terminated or paused. The process shown in FIGS.27A-27E may be a continuous process, with continuous pulling (by thevacuum system 320) and pushing (by the article feeding mechanism 315)through the skinning pipe 310. Alternatively or additionally, theskinning system 300 may be operated in an index mode, in which theprocess may be stopped at one point, and re-started at a different pointduring the process. For example, the skinning system 300 may be operatedto skin one article, and then stopped or paused after the article isskinned, and then re-started to skin another article, rather than beingoperated to skin a plurality of articles in a continuous manner.

FIG. 28 shows an exemplary vacuum system 320. The vacuum system 320 mayinclude the vacuum chuck 1550 with one or more vacuum zones (hence, thevacuum chuck 1550 may be referred to as a multi-zone vacuum chuck 1550).For illustrative purposes, FIG. 28 shows a vacuum system 320 with twovacuum zones (e.g., a multi-zone vacuum system 320). The vacuum system320 may include any number of vacuum zones, such as one, three, four,etc. In the embodiment shown in FIG. 28, the vacuum system 320 includesthe center vacuum zone 1590 and the side vacuum zone 1595. The centervacuum zone 1590 may extend only within one article 1610, while the sidevacuum zone 1595 may extend within both articles 1610 and 1615. This isbecause a donut hole shaped spacer 1605 is disposed between the articles1610 and 1615, and a donut shaped spacer 1600 is disposed at the bottomof the article 1615. When a donut shaped spacer 1600 is disposed betweenthe articles 1610 and 1615, and a donut hole shaped spacer is disposedat the bottom of the article 1615, the center vacuum zone 1590 mayextend within both articles and the side vacuum zone 1595 may extendonly within one article.

The vacuum system 320 may include two or more vacuum ports. For example,the vacuum system 320 may include a first vacuum port 1620 and a secondvacuum port 1625. Both vacuum ports 1620 and 1625 may be connected to avacuum generating machine (not shown) configured to generate a vacuumpressure or vacuum force within the vacuum zones 1590 and 1595. Thefirst vacuum port 1620 may be used for generating the center vacuum zone1590, and the second vacuum port 1625 may be used for generating theside vacuum zone 1595. As shown in FIG. 28, air may flow into thearticles 1610 and 1615 from the side surfaces of the articles. When morethan two vacuum zones are included in the vacuum system 320, the vacuumsystem 320 may include more than two vacuum ports.

FIGS. 29A and 29B show isometric cut-away views of the exemplary vacuumsystems 320 with vacuum chuck 1550 having different sizes. FIG. 29Ashows the vacuum chuck 1550 having a twelve-inch diameter, and FIG. 29Bshows the vacuum chuck 1550 having a seven-inch diameter. Although thevacuum chuck 1550 is shown to have a circular face or shape, the vacuumchuck 1550 may include any other suitable face or shape, such as, forexample, square, rectangle, triangle, polygon, etc. As shown in FIGS.29A and 29B, the vacuum system 320 may include a chuck mount 1630. Thevacuum chuck 1550 may be detached from the chuck mount 1630 and replacedfor a different size. The vacuum chuck 1550 may be mounted to the chuckmount 1630 under a lower surface of the chuck mount 1630. An O-ring seal1635 may be provided between the chuck mount 1630 and the vacuum chuck1550 to seal off the space between the chuck mount 1630 and the vacuumchuck 1550.

The first vacuum port 1620 and the second vacuum port 1625 may bemounted on the chuck mount 1630 (e.g., on a top surface of the chuckmount 1630). The vacuum system 320 may include a tip or tilt plate 1640.The tilt plate 1640 may be mounted on a top surface of the chuck mount1630. One or more force sensors 1645 (e.g., at least one first forcesensor 1645) may be disposed between the tilt plate 1640 and the chuckmount 1630. In some embodiments, the force sensors 1645 may be mountedon the chuck mount 1630. In some embodiments, the force sensors 1645 maybe mounted to a lower surface of the tilt plate 1640, on the uppersurface of the tilt plate 1640, or on the upper carriage 1540. The forcesensors 1645 may be disposed at any other suitable locations on theupper carriage 1540 or the vacuum system 320. The tilt plate 1640 may bemounted to the upper carriage 1540. The force sensors 1645 may beconfigured to measure at least one force (e.g., first force) experiencedby the upper carriage 1540. The force measured by the force sensors 1645may be used to determine the timing of hand-off between the uppercarriage 1540 and the lower carriage 1525 during the skinning process.

The vacuum system 320 may also include a counterbored hole 1650 forreceiving one or more screws or another fastening device, through whichthe vacuum chunk 1550 may be mounted to the chuck mount 1630 (e.g., to abottom surface of the chuck mount 1630). Other suitable fastening meansmay include rods, bolts, nuts, clamps, etc. The fastening means mayenable a fast change of the vacuum chuck 1550 for a different size whenthe size of the articles is changed. As shown in FIGS. 29A and 29B, thevacuum chuck 1550 may include one or more air passages or vacuumchannels 1551 (e.g., two or more vacuum channels 1551). The air passages1551 may communicate with the air flow received from the article withminimal restriction so as to minimize the magnitude of vacuum pressureand/or the vacuum force for holing and pulling the articles. The airpassages 1551 may be in fluid communication with the first vacuum port1620 and the second vacuum port 1625. Each of the first vacuum port 1620and the second vacuum port 1625 may be independently controlled, e.g.,by the control system 400, to provide vacuum pressure to the airpassages 1551 or stop providing vacuum pressure to the air passages1551.

FIGS. 30A and 30B show isometric views of the exemplary vacuum chuck1550 in different sizes. FIG. 30A shows the vacuum chuck 1550 having afirst size (e.g., twelve-inch diameter), and FIG. 30B shows the vacuumchuck 1550 having a different second size (e.g., seven-inch diameter).When the size of the articles to be skinned is changed (e.g., from aseven-inch diameter to a twelve-inch diameter), the vacuum chuck 1550mounted to the chuck mount 1630 may be quickly changed for a differentvacuum chuck with a different size (e.g., diameter).

In some embodiments, the vacuum chuck 1550 may include one or moreintegral molded rubber surfaces. For example, each vacuum chuck 1550shown in FIGS. 30A and 30B may include two integral molded rubbersurfaces 1556 and 1557. The rubber surfaces 1556 and 1557 may beconfigured to seal the top surfaces of the articles when the vacuumchuck 1550 is in contact with the articles, even when the article topsurfaces are not even. The rubber surfaces 1556 and 1557 may also beconfigured to provide an amount of compliance during the hand-off ofarticles that occurs during the skinning process discussed above inconnection with FIGS. 27A-27E, and the force triggered motion controlprocess discussed below.

FIGS. 31A and 31B show an isometric view and a top view of the vacuumsystem 320. As shown in FIG. 31A, the vacuum chuck 1550 may hold botharticles 1610 and 1615 by a vacuum pressure. The force sensors 1645 maybe mounted on the chuck mount 1630, although the force sensors 1645 maybe mounted at any other locations of the vacuum system 320 or the uppercarriage 1540. The force sensors 1645 may be configured to measureforces experienced by the vacuum mount 1630 (and hence the uppercarriage 1540) as a result of a pushing force exerted, e.g., by thearticle feeding mechanism 315, on the lower article 1615 that the vacuumchuck 1550 holds. The force sensors 1645 are not used for measuring thevacuum force generated by the vacuum system 320.

FIG. 31B shows the exemplary locations of the three force sensors 1645relative to the first vacuum port 1620. The first vacuum port 1620 maybe located at the center portion of the chuck mount 1630, which may havea circular top surface. The three force sensors 1645 may be locatedaround the first vacuum chuck 1620 (or the center of the circular topsurface of the chuck mount 1630) at equal distances, forming anequilateral triangle. The distances between one of the force sensors1645 and the center of the circular top surface of the chuck mount 1630are shown in FIG. 31B, as one example configuration. The three forcesensors 1645 may be distributed in other configurations on the chuckmount, which may not form an equilateral triangle. For example, they mayform any triangle. In some embodiments, less than three or more thanthree force sensors 1645 may be used.

Below equations show how the force experienced by the vacuum mount 1630(and hence the upper carriage 1540) may be calculated from the forcesmeasured by the force sensors 1645. For discussion convenience, thethree force sensors 1645 are labeled as “L,” “R,” and “F,” and theforces they measure are labeled as “F_(L),” “F_(R),” and “F,” as shownin FIGS. 31A and 31B. As shown in the equations below, summing the forcemoments (M) about the x-axis (the same direction as “F_(x)”) shown inFIG. 31A yields F_(y) as a function of the forces F_(L) and F_(R)measured by the force sensors “L” and “R.”

ΣM _(x-axis)=0  (B-1)

F _(y) L _(z)+4.42F _(R)−4.42F _(L)=0  (B-2)

F _(y)=(4.42F _(L)−4.42F _(R))/L _(Z)  (B-3)

Summing the force moments about the y axis (the same direction as“F_(y)”) shown in FIG. 31A yields F_(x) as a function of the forcesF_(L), F_(R), and F_(F) measured by the three force sensors “L,” “R,”and “F.”

ΣM _(y-axis)=0  (B-4)

−F _(x) L _(Z)+2.55F _(R)+2.55F _(L)−5.1F _(F)=0  (B-5)

F _(x)=(2.55F _(R)+2.55F _(L)−5.1F)/L _(Z)  (B-6)

The total side force may be:

F _(side)=√{square root over (F _(y) ² +F _(x) ²)}  (B-7)

The force in the z-direction (same as the F_(z) direction shown in FIG.31A) may be calculated by summing the three forces measured by the threeforce sensors:

F _(z) =F _(L) +F _(R) +F _(F)  (B-8)

The force sensors 1645 may transmit, via a wired or wireless network,electrical signals to the skinning control system 410, which may use thesignals to calculate the forces F_(R), F_(F), and F_(L) as a function oftime. These force measurements may be input into the above equations(B-1) to (B-8) to calculate process forces F_(x), F_(y), and F_(z). Theprocess forces may be used in process monitoring, debug, and controls,such as, for example, a force triggered motion control of the skinningsystem 300 discussed below.

FIG. 32 shows an isometric view of the exemplary manifold or manifoldassembly 305. As shown in FIG. 32, the manifold 305 may be mounted tothe frame structure 1500 through one or more mounting bracket 1505. Inthe embodiment shown in FIG. 32, two mounting brackets 1505 areincluded, one on each side of the manifold 305, although any suitablenumber (e.g., one, three, four, etc.) of mounting brackets 1505 may beused. The manifold 305 may be mounted to the mounting bracket 1505through one or more fastening devices 1655. FIG. 32 shows four fasteningdevices 1655. In some embodiments, any number (e.g., one, two, three,six, etc.) of fastening devices 1655 may be used. The fastening devices1655 may be any suitable fastening devices, such as clamps, screws,bolts and nuts, etc.

The skinning pipe 310 may be mounted at a center portion of the manifold305, for example, inside a hole of the manifold 305. For illustrativepurposes, two articles 1660 and 1665 are shown in the skinning pipe 310.The skinning pipe 310 may be configured to receive the articles 1660 and1665 and apply the flowable mixture to the articles 1660 and 1665 as thearticles 1660 and 1665 move axially along the inner space of theskinning pipe 310.

Referring to FIG. 32, at least one laser device 1555 may be disposedadjacent the outlet (e.g., the upper open end) of the skinning pipe 310and configured to monitor and/or detect a defect in a skinned article orat least partially skinned article, as the article moves out of theskinning pipe 310. The laser device 1555 may be referred to as a defectmonitoring laser device 1555. FIG. 32 shows four laser devices 1555disposed adjacent the outlet of the skinning pipe 310 for monitoringand/or detecting the defect. In some embodiments, the laser devices 1555may also be mounted on the mounting brackets 1505 or a dedicatedmounting bracket. In some embodiments, the laser devices 1555 may bemounted on a top or side surface of the manifold 305. Other suitablenumbers (e.g., one, two, three, five, six, etc.) of laser devices 1555may be used.

Referring to FIG. 32, at least one laser device 1560 may be disposedadjacent an inlet (e.g., the lower open end) of the skinning pipe 310and configured to measure a dimension (e.g., diameter, radius,circumference, axial length, and/or outer peripheral length) of anincoming unskinned article. The laser device 1560 may be referred to asdimension measuring laser device 1560. In the embodiment shown in FIG.32, four laser devices 1560 are disposed adjacent the inlet of theskinning pipe 310 for measuring the dimension of unskinned articles(three are visible in FIG. 32, and one is obscured). In someembodiments, the laser devices 1560 may be mounted on a lower or sidesurface of the manifold 305. In some embodiments, the laser devices 1560may be mounted on the lower portion of the mounting bracket 1505 or adedicated mounting bracket. In some embodiments, the laser devices 1560may be mounted at a middle point between the manifold 305 and the lowestposition of the article feeding mechanism 315. Other suitable numbers oflaser devices 1560 (e.g., one, two, three, five, six, seven, eight,etc.) may also be used. In some embodiments, the laser devices 1560 maybe used to measure the diameter of the unskinned articles.

FIG. 33 shows an isometric view of the exemplary manifold or manifoldassembly 305. As shown in FIG. 33, the upper carriage 1540 may moveclose to the manifold 305. The vacuum chuck 1550 may hold the article1660 and pull the article 1660 through the skinning pipe 310. Thearticle 1660 may be at least partially skinned with the flowablemixture. The vacuum chuck 1550 may pull the article 1660 as the article1660 moves axially along the inner space of the skinning pipe 310 toreceive the flowable mixture.

In some embodiments, the manifold 305 may be placed on a precisionmachined pad (not shown), which may be a part of the mounting bracket1505. The manifold 305 may include at least one locating pad 1670 (e.g.,a plurality of locating pads 1670) configured to aid in positioning themanifold 305 on the mounting bracket 1505. In the embodiment shown inFIG. 33, six locating pads 1670 are included and distributed at suitablelocations around the manifold 305. Other suitable numbers (e.g., onetwo, three, four, five, seven, eight, etc.) of locating pads 1670 may beused.

The manifold 305 may include at least one locating block 1675 (e.g., aplurality of locating blocks 1675) distributed at suitable locationsaround the manifold 305. The locating blocks 1675 may be screwed orotherwise secured to the mounting bracket 1675. The locating blocks 1675may be configured to aid in positioning the manifold 305 on the mountingbracket 1505. In the embodiment shown in FIG. 33, six locating blocks1675 are included and distributed at suitable locations. Other suitablenumbers (e.g., one, two, three, four, five, seven, etc.) of locatingblocks 1675 may also be used. The locating blocks 1675 may or may not bepart of the manifold assembly 305.

Referring to FIG. 33, the locating pads 1670 and the locating blocks1675 may enable fast mounting or assembling of the manifold 305 onto themanifold mounting bracket 1505 at the precise locations. For example,when articles of different sizes are used, the manifold 305 may need tobe changed for a skinning pipe 310 of a different size. In somesituations, the manifold 305 may need to be disassembled to be servicedor changed. The manifold 305 may be disassembled from the mountingbracket 1505, and a new or serviced manifold 305 may be mounted backonto the mounting bracket 1505. The locating pads 1670 and locatingblocks 1675 may enable precise positioning and mounting of the newmanifold 305 such that the skinning pipe 310 is back to its previousposition within a small tolerance. The position of the skinning pipe mayinclude positions in two horizontal directions and one verticaldirection, one tip angle, and one tilt angle. The need for realigningthe skinning pipe 310 and/or the manifold 305 after changing, servicing,or disassembling the manifold 305 or the skinning pipe 310 may bereduced or eliminated.

FIG. 33 also shows one or more pressure sensors 1678 mounted to theskinning pipe 310. The pressure sensors 1678 may be mounted to an upperportion of the skinning pipe 310 above the top surface of the manifold305. The pressure sensors 1678 may be mounted on an outer surface of theskinning pipe 310 and may penetrate through the wall 1680 (shown in FIG.34) of the skinning pipe 310. An end portion of the pressure sensors1678 may be disposed adjacent the inner surface of the wall 1680. Thepressure sensors 1678 may be configured to measure a pressure in anannular space (or gap) between the article 1660 and the skinning pipe310. This pressure may or may not be the same as the skinning pipepressure measured by the pressure sensors 330 (shown in FIG. 1), whichmay be mounted to a lower portion of the skinning pipe 310. In someembodiments, six pressure sensors 1678 may be used (two are shown inFIG. 33 for illustrative purposes). In some embodiments, other suitablenumbers (e.g., one, two, three, four, five, seven, eight, etc.) ofpressure sensors 1678 may be used.

FIG. 34 shows an isometric view of an exemplary manifold or manifoldassembly 305. The skinning pipe 310 ma include a wall 1680 defining aninner space. The wall 1680 may include a plurality of holes 1683 (e.g.,radial holes) configured to direct the flowable mixture flowing from themanifold 305 into the inner space (e.g., the annular gap between anarticle and the skinning pipe 310). The inner space of the skinning pipe310 may be configured to be slighter larger than the volume of anunskinned article. Thus, when the article is disposed within the innerspace, there is a small annular space (or gap) between the outer surfaceof the article and the inner surface of the wall 1680. Flowable mixturemay flow into the annular space through the holes 1683 and may attach tothe outer surface of the article. In some embodiments, the wall 1680 maybe curved (e.g. when the skinning pipe 310 has a circular cross sectionshape). The skinning pipe 310 may have a different cross section shape,such as, for example, triangle, square, rectangle, polygon, ellipse,etc., and the wall 1680 may not be curved. The shape of the crosssection of the skinning pipe 310 may match that of the articles to beskinned.

Referring to FIG. 34, the manifold 305 may include an upper ring 1685.The skinning pipe 310 may be mounted to the upper ring 1685 with tightradial clearance such that the skinning pipe 310 and the upper ring 1685may be disassembled and reassembled with their centerline relations andtip/tilt errors remain within a small value (e.g., approximately within0.0005 inches).

The manifold 305 may include an upper manifold piece 1690 and a lowermanifold piece 1695 joined together. The upper ring 1685 may be mountedto the upper manifold piece 1690 with a tight radial clearance such thatthe centerline relations and the tip/tilt errors of these parts remainwithin a small value (e.g., approximately 0.0005 inches), even as theyare disassembled or reassembled. The upper manifold piece 1690 and thelower manifold piece 1695 may be joined together to form the manifold305, and may be taken apart for cleaning or servicing.

Referring to FIG. 34, the manifold 305 may include one or more pressuresensors 325. Each of the pressure sensors 325 may be mounted on themanifold 305 adjacent an inlet 1700 of the manifold 305 that receivesthe flowable mixture from the mixture delivery system 200. The pressuresensors 325 may be configured to measure a pressure at the manifoldinlet 1700 (e.g., manifold pressure). FIG. 34 shows two inlets 1700 andtwo pressure sensors 325. The manifold 305 may include other number(such as one, three, four, etc.) of inlets 1700 and pressure sensors325. In some embodiments, the manifold 305 may further include aplurality of lifting hooks 1705 configured to be used for lifting up themanifold 305 (e.g., the entire manifold 305 or the upper manifold piece1690).

FIG. 35 shows a cross sectional view of the exemplary manifold 305. Thecross sectional view is taken from a line connecting the two inlets 1700of the manifold 305 shown in FIG. 34. The manifold 305 may include oneor more locating cylinders 1710 and one or more locating pins 1715. Theone or more locating cylinders 1710 may be disposed within the lowermanifold piece 1695, and the one or more locating pins 1715 may bedisposed within the upper manifold piece 1690. In some embodiments, thelocating cylinders 1710 may be disposed within the upper manifold piece1690 and the locating pins 1715 may be disposed within the lowermanifold piece 1695.

The locating cylinders 1710 and the locating pins 1715 may be configuredto aid in precise locating and positioning of the upper manifold piece1690 an the lower manifold piece 1695. For example, the locatingcylinders 1710 and the locating pins 1715 may engage with one anotherfor precisely locating and joining the upper manifold piece 1690 and thelower manifold piece 1695. In the embodiment shown in FIG. 34, twolocating pins 1715 and two locating cylinders 1710 are included. Othersuitable numbers (e.g., one, three, four, etc.) of locating pins 1715and locating cylinders 1710 may be included in the manifold 305. Thelocating pins 1715 and the locating cylinders 1710 may be made of a hardmaterial that may experience minimal wear as they are removed andreplaced repeatedly. The clearance from the locating pins 1715 to thelocating cylinders 1710 may be a small clearance (e.g., less than 0.001inches), such that the lower manifold piece 1695 may be located in twohorizontal directions within a reasonably small deviation even afterrepeated disassembly and reassembly.

As shown in FIG. 35, the manifold 305 may include a lower ring 1720. Thelower ring 1720 may be disposed at a lower portion of the skinning pipe310, e.g., under the lower manifold piece 1695. The lower ring 1720 maysurround an outer surface of the skinning pipe 310. In some embodiments,the lower ring 1720 may be mounted to the lower manifold piece 1695using suitable fastening devices, such as screws, bolts, nuts, etc. Thelower ring 1720 may be configured to change or adjust the space adjacentthe skinning pipe 310 available for the flowable mixture to flow to theholes 1683 of the skinning pipe 310. When the space adjacent theskinning pipe 310 is increased for the flowable mixture, the pressurewithin the flowable mixture adjacent the skinning pipe 310 (e.g., theskinning pipe pressure) may be reduced. When the space adjacent theskinning pipe 310 is reduced for the flowable mixture, the pressurewithin the flowable mixture adjacent the skinning pipe 310 (e.g., theskinning pipe pressure) may be increased. The lower ring 1720 may move,under actuation of an actuator, up and down along the outer surface ofthe skinning pipe 310, to change the space adjacent the skinning pipeavailable for the flowable mixture to flow. The lower ring 1720 mayprevent the flowable mixture from leaking from a gap between the lowerring 1720 and the skinning pipe 310, which may be a tight fit that maybe less than 0.003 inches on radius. The manifold 305 may include one ormore plugs 1725. Each plug 1725 may be disposed adjacent the inlet 1700and configured to prevent the flowable mixture from leaking from theinlet 1700.

FIG. 36 shows an isometric view of the exemplary manifold 305 with theupper manifold piece 1690 removed. FIG. 36 shows the manifold 305 withthe upper manifold piece 1690 removed to expose the lower manifold piece1695. The lower manifold piece 1695 may include a plurality of groovesor channels 1730 formed thereon. The upper manifold piece 1690 maylikewise include grooves or channels that match the grooves 1730 of thelower manifold piece 1695. When the lower manifold piece 1695 and theupper manifold piece 1690 are joined together, the grooves on therespective manifold piece may form complete channels for the flowablemixture to flow. The grooves 1730 may include a plurality of bifurcatedsub-grooves, forming a plurality of distribution channels fordistributing the flowable mixture to the skinning pipe 310. The flowablemixture may enter the manifold from the inlets 1700, and flow throughthe grooves 1730, and then through the holes 1683 of the wall 1680 intothe annular gap between the article and the inner surface of the wall1680.

Pressure Relief System

FIG. 37 shows an at least partially skinned article 1740 with a ringdefect 1745 on a skin 1750. The ring defect 1745 on the skin is a ringof extra flowable mixture. The ring defect 1745 may be caused by asudden pressure change in the skinning pipe 310. For example, such adefect may occur when the skinning system 300 is halted and the pump 235is stopped and/or the delivery valve 245 has been closed. Such a defectmay also occur when there is no pressure relief (or release) mechanismactuated or activated to reduce the pressure within the manifold 305and/or the skinning pipe 310. In such situations, the residual pressureremaining within the internal passages (e.g., grooves 1730) of themanifold 305 may continue to push the flowable mixture out of the top ofthe skinning pipe 310, creating the ring defect 1745. To address thisproblem, the disclosed manifold 305 may include a pressure relief systemconfigured to effectively prevent sudden pressure changes that lead tothe formation of ring defects 1745.

FIG. 38 shows an isometric view of the exemplary manifold 305 having apressure relief system 1755 (or pressure adjustment system 1755). Thepressure relief system 1755 may include one or more actuators 1760 (alsoreferred to as pressure release actuators 1760). In the embodiment shownin FIG. 38, the pressure relief system 1755 includes four pressurerelease actuators 1760. Other suitable numbers (e.g., one, two, three,five, six, etc.) of pressure release actuators 1760 may be used.

FIG. 39 shows an isometric cut-away view of the exemplary manifold 305with the pressure release actuators 1760. The cut-away view may be takenalong any straight line connecting two pressure release actuators 1760shown in FIG. 38. FIG. 39 shows the locations of the pressure releaseactuators 1760 and the lower ring 1720.

FIG. 40 shows an isometric bottom view of the exemplary manifold 305.FIG. 40 shows the bottom configuration of an exemplary manifold 305.FIG. 40 shows the location of the plugs 1725. FIG. 40 also shows thelocations of the pressure sensors 330 (also shown in FIG. 1). Thepressure sensors 330 may be mounted to the lower ring 1720, whichsurrounds the lower portion of the skinning pipe 310. In someembodiments, the pressure sensors 330 may be mounted to the lowermanifold piece 1695. In the embodiment shown in FIG. 40, there are sixpressure sensors 330. Other numbers (e.g., one, two, three, four, five,seven, etc.) of pressure sensors 330 may be used.

The pressure sensors 330 may be configured to measure a pressure of theflowable mixture adjacent the skinning pipe 310. The pressure may bemeasured at a manifold exit or an inlet of the skinning pipe 310 that isin fluid communication with the manifold exit. The inlet of the skinningpipe 310 for the flowable mixture refers to a location at the interfaceof the manifold 305 and the skinning pipe 310, where the flowablemixture flows from the manifold 305 to the skinning pipe 310. The inletof the skinning pipe may be adjacent the wall 1680 of the skinning pipe310. The pressure measured by the pressure sensors 330 may beinterchangeably referred to as the skinning pipe pressure, the pressureof the skinning pipe, the unipipe pressure, the pressure of the unipipe,the pressure of the pipe, or the pipe pressure. The skinning pipepressure may reflect the pressure of the flowable mixture within themanifold 305 before the flowable mixture enters the inner space of theskinning pipe 310 through the holes 1683. The pressure relief system1755 may be configured to adjust the pressure of the flowable mixtureadjacent the skinning pipe 310 (e.g., adjust the skinning pipepressure).

As shown in FIG. 40, the manifold 305 may include one or more upperreceivers 1765. In the embodiment shown in FIG. 40, four upper receivers1765 are included. Other suitable numbers (e.g., one, two, three, five,six, etc.) of upper receivers 1765 may be used. The manifold 305 mayinclude one or more lower receivers 1770. In the embodiment shown inFIG. 40, four lower receivers 1770 are included. Other suitable numbers(e.g., one, two, three, five, six, etc.) of lower receivers 1770 may beused. The upper receivers 1765 and the lower receivers 1770 may be partof the pressure relief system 1755. The upper receivers 1765 may belocated above the lower receivers 1770.

FIG. 41 shows an isometric cut-away view of the exemplary manifold 305with the skinning pipe 310 and the pressure release actuator 1760. Thepressure release actuator 1760 may be any suitable actuator configuredto actuate or move the lower ring 1720. In some embodiments, thepressure release actuator 1760 may be a pneumatic cylinder typeactuator. For example, the pressure release actuator 1760 may include apneumatic cylinder (e.g., an air cylinder) 1775.

The air cylinder 1775 may be mechanically connected with an upper end ofa threaded rod 1780. The lower end of the threaded rod 1780 may extendinto a cavity formed by the upper receiver 1765 and the lower receiver1770. One or more locking nuts 1785 may be mounted to the lower end ofthe threaded rod 1780 within the cavity formed by the upper receiver1765 and the lower receiver 1770. Both the upper receiver 1765 and thelower receiver 1770 may be mounted to the lower ring 1720. For example,the upper receiver 1765 may be mounted to a horizontally extendedportion 1790 of the lower ring 1720, e.g., through screws or otherfastening means. The lower receiver 1770 may be mounted to a verticallyextended portion 1795 of the lower ring 1720, e.g., through screws orother connecting means.

The pressure release actuator 1760 may be other type of actuators formoving the lower ring 1720. For example, the pressure release actuator1760 may not include an air cylinder, but instead, may include anelectrical servo motor driven actuator. In some embodiments, the lowerring 1720 may be moved up and down in an abrupt manner. In someembodiments, the lower ring 1720 may be moved up and down smoothly.

Referring to FIG. 41, the pressure release actuator 1760 may include astroke adjustment spacer 1800 disposed surrounding a top end of the aircylinder 1775. The stroke adjustment spacer 1800 may be used to adjustthe stroke of the air cylinder 1775. The distance the lower ring 1720moves may be determined by the length of the stroke adjustment spacer1800. The pressure release actuator 1760 may also include a stop nut1805 located at a top end of the air cylinder 1775. The stop nut 1850may hit upon the stroke adjustment spacer 1800, and be stopped by thestroke adjustment spacer 1800.

The lower ring 1720 may be coupled to a space 1810 formed adjacent theskinning pipe 310, through which the flowable mixture flows to the holes1683 in the skinning pipe 310. The space 1810 is shown to have atrapezoidal shape in the cut-away view shown in FIG. 41. In someembodiments, the space 1810 may have any other suitable shape, such as,for example, triangle, rectangle, square, circle, ellipse, polygon, etc.In some embodiments, the space 1810 may be part of the manifold 305.

The space 1810 available for the flowable mixture to flow may beadjusted by the lower ring 1720 as the lower ring 1720 moves up and downalong the outer surface of the skinning pipe 310. When the lower ring1720 moves down, the volume of the space 1810 available for the flowablemixture to flow may be increased, thereby reducing the pressure of theflowable mixture (e.g., the skinning pipe pressure) before the flowablemixture flows through the holes 1683. When the lower ring 1720 moves up,the volume of the space 1810 available for the flowable mixture may bereduced, thereby increasing the pressure of the flowable mixture beforethe flowable mixture flows through the holes 1683. The space 1810 may bein fluid communication with other parts of the internal passages (e.g.,grooves 1730) for flowing the flowable mixture. Thus, changing thevolume of the space 1810 may also change the total volume of theinternal passages available for the flowable mixture to flow, therebyaffecting the pressure within the internal passages of the manifold 305.

Referring to FIG. 41, in some embodiments, the pressure relief system1755 may be configured such that when it moves the lower ring 1720 up,the volume of the space 1810 (and hence the volume of the internalpassages) may be increased, thereby reducing the skinning pipe pressure.When the pressure relief system 1755 moves the lower ring 1720 down, thevolume of the space 1810 (and hence the volume of the internal passages)may be reduced, thereby increasing the skinning pipe pressure. In someembodiments, the pressure relief system 1755 may be configured such thatwhen it moves the lower ring 1720 up, the volume of the space 1810 (andhence the volume of the internal passages) may be reduced, therebyincreasing the skinning pipe pressure. When the pressure relief system1755 moves the lower ring 1720 down, the volume of the space 1810 (andhence the volume of the internal passages) may be increased, therebyreducing the skinning pipe pressure.

Referring to FIG. 41, during operations, the air cylinder 1775 may moveup and down under air pressure, causing the connected threaded rod 1780to move up and down. When the threaded rod 1780 moves up, the lockingnuts 1785 may strike the upper receiver 1765, causing the lower ring1720 to move up due to the connection between the upper receiver 1765and the horizontally extended portion 1790. When the threaded rod 1780moves down, the locking nuts 1785 may strike the lower receiver 1770,causing the lower ring 1720 to move down due to the connection betweenthe lower receiver 1770 and the vertically extended portion 1795.

In some embodiments, when the skinning process has been stopped (e.g., asudden system shut down), the pressure relief system 1755 may beactivated to increase the space 1810 adjacent the skinning pipe 310(e.g., by moving the lower ring 1720 down), thereby reducing thepressure of the internal passages (e.g., grooves) through which theflowable mixture flows. This may prevent the flowable mixture frombleeding at the exit of the skinning pipe 310 and creating a ring defect1745 on the article that is still disposed within the skinning pipe 310when the skinning process is stopped. This may also eliminate the needfor an operator to enter the skinning cell and wipe off the excessflowable mixture from the exit of the skinning pipe 310.

FIG. 42 shows the pressure relief effect of the exemplary pressurerelief system 1755. FIG. 42 shows a plot of measured manifold pressurevalues and skinning pipe pressure values as a function of time. Thecurve labeled “A” corresponds to the manifold pressure. The manifoldpressure may be measured by one or more of pressure sensors 325, whichmay be located the inlets 1700 or ahead of the cement distributiongrooves 1730. The curve labeled “B” corresponds to the skinning pipepressure (or unipipe pressure). The skinning pipe pressure may bemeasured by one or more of the pressure sensors 330 shown in FIG. 40.The pump 235 in the mixture delivery system 200 was shut off fiveminutes prior to time zero. The residual pressures remain in the twolocations where the pressure sensors 325 are located, due to the natureof the flowable mixture (e.g., cement) to retain pressure locally withinan enclosed volume even if the source of the pressurization is stopped.

As shown in FIG. 42, the skinning pipe pressure in the region closest tothe article remains at approximately 1.2 psig until the pressure reliefsystem 1755 was actuated at a time corresponding to 43 seconds on theplot. The skinning pipe pressure then dropped to approximately zeropsig. Because the skinning pipe pressure dropped to zero as soon as thearticle motion was stopped, no excess cement oozed from the top of theskinning pipe 310. Accordingly, no ring defect 1745 as described in FIG.37 was created and the article had sufficient skin quality to meetcustomer requirements. In addition, no excess flowable mixture was lefton the top surface of the skinning pipe 310 that would cause “dragging”defects on subsequent articles that were skinned. Also, no operatorintervention was needed to clean the excess flowable mixture (e.g.,cement) from the top face of the skinning pipe 310 and production couldresume without lost time, resulting in improved manufacturingefficiency.

FIG. 43 shows a cross sectional view of the exemplary manifold 305having the pressure relief system 1755. In the embodiment shown in FIG.43, the pressure relief system 1755 may include one or more electricalservo driven actuators 1815, which may be, for example, ball screwactuators 1815. The ball screw actuator 1815 enables smooth actuation(e.g., movement) of the lower ring 1720. Any other type of suitableactuators that may enable smooth or incremental control the movement ofthe lower ring 1720 may be used. The smooth actuation of the lower ring1720 may enable more accurate control of the skinning pipe pressure,thereby improving the skin quality control. The ball screw actuator 1815may be used in addition to or instead of the air cylinder type pressurerelease actuators 1760 depicted in FIGS. 38, 39, and 41. In someembodiments, these two types of actuators may be used together. Like theair cylinder type pressure release actuators 1760, the ball screwactuators 1815 may also be used for abrupt type actuation of the lowerring 1720.

FIG. 44 shows an isometric view of the exemplary manifold 305 with theexemplary pressure relief system 1755. The pressure relief system 1755may include at least one ball screw type actuator 1815, replacing oneair cylinder type pressure release actuator 1760 shown in FIG. 38. Morethan one ball screw type actuator 1815 may be used to replace more thanone air cylinder type pressure release actuator 1760. In someembodiments, the pressure relief system 1755 may use only one ball screwtype actuator 1815. In some embodiments, the pressure relief system 1755may use a combination of one or more ball screw type actuators 1815 andone or more air cylinder type pressure release actuators 1760. In someembodiments, the pressure relief system 1755 may include only one ormore ball screw type actuators 1815 (e.g., four ball screw typeactuators).

Skin Thickness Sensor

In axial skinning, eccentricity between the article and the skinningpipe 310 may create skin thickness nonuniformity. A system and method isdeveloped to measure the skin thickness at a point around thecircumference of the skinning pipe 310 as the article is being skinned.The skin thickness may be used for control of cracks that may occur inthe skin during a drying process. A higher skin thickness may result ina greater incidence of cracks. A valving method is also introduced bywhich the skin thickness measurements may be used as feedback for acontrol method. Skin thickness may be continuously monitored andmeasured. The measured skin thickness may also be used as feedback tomachines upstream that grind unskinned articles to a specific dimension(e.g., diameter) to produce unskinned articles that will have skinthicknesses that will not experience cracking during the drying process.In addition, by measuring and monitoring the skin thickness as thearticles are being skinned in the skinning pipe 310, blockages in theflow of the skinning material through the distribution grooves 1730 inthe manifold 305 may be detected, and the skinning process may bestopped to prevent a large number of scrap articles to be produced. Theblockages within the manifold 305 may be removed in time.

FIG. 45 shows an isometric view of the exemplary manifold 305 having oneor more skin thickness sensors 1820. In the embodiment shown in FIG. 45,there are four skin thickness sensors 1820. Other suitable numbers(e.g., one, two, three, five, six, etc.) of skin thickness sensors mayalso be used. Each skin thickness sensor 1820 may be integrated with thewall 1680 of the skinning pipe 310. For example, the skin thicknesssensor 1820 may be mounted to the outer surface of the wall 1680 of theskinning pipe 310, and may penetrate through the wall 1680. One end ofthe skin thickness sensor 1820 may be located adjacent the inner surfaceof the wall 1680, as shown in FIG. 45.

FIG. 46 shows a cross sectional isometric view of the exemplary skinningpipe 310 mounted with the exemplary skin thickness sensor 1820. The skinthickness sensor 1820 may include a probe body 1825 mounted to the outersurface of the wall 1680 of the skinning pipe 310 by one or moresuitable fasteners, such as for example, one or more screws 1830. Theprobe body 1825 may penetrate through the wall 1680 of the skinning pipe310. One end 1835 of the probe body 1825 may be located adjacent theinner surface of the wall 1680, as shown in FIG. 46.

The skin thickness sensor 1820 may include one or more conductors 1840(e.g., at least one conductor 1840) connected to a power source and acircuit for supplying a voltage and/or electric current to the skinthickness sensor 1820. Exemplary power source and circuit are shown inFIG. 48. The conductors 1840 may be disposed or housed at leastpartially within the probe body 1825. The probe body 1825 may include atleast one insulating material configured to electrically insulate theconductors 1840 from one another and from the skinning pipe 310. In theembodiment shown in FIG. 46, two conductors 1840 are shown. In someembodiments, one or more than two conductors 1840 may be used.

Referring to FIG. 46, end portions of the conductors 1840 may be locatedadjacent the inner surface of the wall 1680. As a skinned article movesalong the inner space of the skinning pipe 310 and passes the endportions of the conductors 1840, the end portions of the conductors 1840may be in contact or nearly in contact with the skin (e.g., the coatedflowable mixture), yet does not introduce any defect or marks on theskin. Through the conductors 1840 and the power source in the circuit, acurrent maybe applied to the skin (e.g., flowable mixture) on theskinned article. The current may flow through one of the conductors1840, the skin, and to another one of the conductors 1840. As a result,some characteristics of the circuit may be changed due to the currentflowing through the skin. The changing characteristics of the circuitmay be used to calculate the thickness of the skin based on a knownrelationship between the characteristics and the thicknesses of theskin.

The skin thickness sensor 1820 may include one or more spacers 1845located between the probe body 1825 where the screws 1830 are located,and the outer surface of the wall 1680. The spacers 1845 may include acurved surface configured to match the curvature of the curved wall1680, thereby making the skin thickness sensor 1820 better secured tothe curved wall 1680.

FIGS. 47A and 47B schematically show the exemplary skinning pipe 310mounted with the exemplary skin thickness sensor 1820. FIG. 47A shows atop view (viewed from the side of the skinning pipe 310 in a directionperpendicular to the surface of the skin thickness sensor 1820 shown inFIG. 44), and FIG. 47B shows a cross sectional view (viewed from the topof the skinning pipe 310).

The skin thickness sensor 1820 may include an insulator 1850, which maybe any suitable insulator, such as for example, a ceramic insulator, aplastic insulator, etc. The insulator 1850 may surround the conductors1840 and may form the probe body 1825 shown in FIG. 46. As shown in FIG.47B, as an article 1860 with a skin 1855 (i.e., skinning material orflowable mixture 1855) moves upward out of the skinning pipe 310, theskin thickness sensor 1820 may be activated (e.g., by the skinningcontrol system 410) to apply a voltage and/or current to the skin 1855through the conductors 1840. The conductors 1840 may be connected to acircuit having at least one power source for applying the current. Thecurrent may flow through the skin 1855 and the circuit. One or morecharacteristics of the circuit may change as current is applied to theskin having different thicknesses. Based on a predefined, established,or calibrated relationship between the circuit characteristics and theskin thicknesses, the actual skin thickness may be calculated using theskin thickness sensor 1820 and the measured circuit characteristics.

FIG. 48 shows an exemplary bench test prototype 1865 that may be used toestablish, calibrate, or predefine a relationship between a circuitcharacteristic and the skin thicknesses. The test prototype 1865 mayinclude a plastic insulator 1870. A plastic shim 1875 may be stacked onthe plastic insulator 1870. The plastic shim 1875 may include a portionfilled with the skinning material (e.g., flowable mixture) 1855. Theinsulator 1850, which may be a plastic insulator, may be placed on tothe plastic shim 1875. The insulator 1850 may include two conductors1840 disposed therein. The conductors 1840 may be surrounded by theinsulator 1850. The conductors 1840 may be copper tubes, or may includeany other conductive materials.

The conductors 1840 may be connected to a circuit 1880 having a circuitportion 1885, which may include a resistor. The circuit 1880 may alsoinclude a power source 1890 (e.g., a voltage and/or current source1890), which may be a battery or a power supply unit. The resistor mayhave any suitable value, such as, for example, 10 k Ohms, 100 k Ohms, 1k Ohms, etc. The resistor may be connected in series with the conductors1840. The power source 1890 may apply a voltage and/or current to thecircuit 1880 formed by the resistor, the conductor 1840, and the skinmaterial 1855. The voltage across the resistor may be measured, forexample, by a voltmeter (not shown). Although a resistor is used as anexample of the circuit portion across which a voltage may be measuredfor determining the thickness of the skin (e.g., flowable mixtureapplied to the article), the circuit portion 1885 may include additionaland/or alternative electric components, such as capacitors. Although themeasured voltage may be used for determining the thickness of the skin,a measured charge of a capacitor may also be used for determining thethickness of the skin.

The measured voltages are plotted against different skin thicknesses,and the relationship is shown in FIG. 49. FIG. 49 shows a relativelylinear relationship between the measured voltages across the resistor1885 and the thickness of the skin material when the thickness of theskin material is less than 1.5 mm. The relationship shown in FIG. 49 maybe used, e.g., by the control system or a dedicated controller, formeasuring or calculating actual thicknesses of the skin during theskinning process based on voltages measured across resistors in circuitssimilar to the circuit 1880. Circuits similar to the circuit 1880 shownin FIG. 48 (e.g., including a power source and a resistor) may beconnected to the conductors 1840 of the sensor 1820 to measure the skinthickness based on a pre-established or pre-defined relationship betweenthe skin thicknesses and the voltage across the resistor (e.g., such asthe relationship shown in FIG. 49). The circuit for applying the currentto the skin and for measuring the voltage across the circuit portion(e.g., the resistor) may be included as part of the sensor 1820 or maybe separate from the sensor 1820.

FIG. 50 shows a schematic diagram of a system 1895 configured to controlflow of flowable mixture based on skin thickness measurements. FIG. 50schematically shows the manifold 305 with the skinning pipe 310 anddistribution grooves 1730 for delivering the flowable mixture to theskinning pipe 310. The manifold 305 may include one or more inlets. Forillustrative purposes, FIG. 50 shows four inlets 1901, 1902, 1903, and1904. The inlets 1901, 1902, 1903, and 1904 are fluidly connected withthe delivery line 240 and configured to receive the flowable mixturefrom the mixture delivery system 200 through the delivery line 240. Thepump 235 may pump the flowable mixture to the inlets 1901, 1902, 1903,and 1904 through the delivery line 240. Any number of inlets may beincluded in the manifold 305, such as, for example, one, two, three,five, six, etc.

As shown in FIG. 50, the system 1895 may include one or more valvesdisposed upstream of the inlets 1901, 1902, 1903, and 1904 forcontrolling the flow of the flowable mixture into the inlets. In theembodiment shown in FIG. 50, four valves 1911, 1912, 1913, and 1914 areshown. The number of valves may or may not match the number of inlets.For example, even if there are four inlets, the system 1895 may use onlytwo valves, one for each pair of inlets. When the manifold 305 shown inFIG. 36 is used, which includes two inlets 1700 at two sides, similarconfiguration may be used for controlling the flow of the flowablemixture into the inlets 1700 based on the measured skin thickness. Fourskin thickness sensors 1820 are shown in FIG. 50. Other number (e.g.,one, two, three, five, etc.) of skin thickness sensors 1820 may also beused. The system 1895 may enable a feedback control in which themeasured skin thickness may be used as real-time feedback to control thearticle such that it is centrally located within the skinning pipe 310as it moves through the skinning pipe 310 to receive the flowablemixture, thereby improving the uniformity of the skin thickness.

The measured skin thickness may be used to extract information that maybe useful for controlling the mixture delivery system 200 (e.g., theproperties of the flowable mixture) and the skinning system 300 (e.g.,the skinning process). FIG. 51 shows measured skin thickness outputsignals versus time from two skin thickness sensors 1820 (e.g., frontskin thickness sensor and right skin thickness sensor). The two skinthickness sensors 1820 may be located at different positions (e.g.,front and right) of the skinning pipe 310. The skinning pipe pressure(e.g., unipipe pressure) and the position of the lower and uppercarriages 1525 and 1540 (which are referred to as the lower and upperaxes in FIG. 51) are also plotted for reference.

FIG. 51 shows a strong correlation between skin thickness output signalsand average skinning pipe pressure (e.g., unipipe pressure), indicatingthat the skin thickness sensors 1820 are also able to detect the watercontent of the flowable mixture (e.g., cement), which may be driven intothe article (e.g., a cellular ceramic filter substrate) at a higher ratewhen the skinning pipe pressure (e.g., unipipe pressure) is higher. FIG.51 also shows a discernible oscillation in the output signals of theskin thickness sensors 1820, indicating that the alternating nature ofvacuum pressure applied to the internal volume of the article also hasan impact on the output signals of the skin thickness sensors 1820. Thisalso seems to indicate that the impact of water content in the skinmaterial (e.g., flowable mixture) is a function of the vacuum that isdrawing the skin material into the article. Information about the watercontent in the wet flowable mixture (e.g., cement) as it is beingskinned may be used in a process control to be correlated with skinflaws in the skinned articles.

FIG. 52 schematically shows the exemplary laser device 1560 formeasuring the dimension (e.g., diameter, radius, circumference, axiallength, and/or outer peripheral length) of an unskinned article. In oneembodiment, the laser device 1560 may be used to measure the diameter ofthe unskinned article. As shown in FIGS. 26 and 32, the skinning system300 may include one or more laser devices 1560 configured to measure thedimension of an unskinned article. The laser devices 1560 may bereferred to as the dimension measuring laser devices 1560. The laserdevices 1560 may be mounted adjacent an inlet of the skinning pipe 310,e.g., under the manifold 305. The schematic diagram of FIG. 52 shows howthe laser devices 1560 measure the dimension (e.g., diameter), and doesnot reflect the actual positions of the laser devices 1560. Two laserdevices 1560 are shown for illustrative purposes. Other number (e.g.,one, three, four, five, six, seven, eight, etc.) of laser devices 1560may be used. As shown in FIG. 52, each laser device 1560 may include alaser unit 1920 and an image capturing device 1925. The laser unit 1920may emit a laser. In some embodiments, the laser unit 1920 may be a linelaser scanner, which may emit a line laser 1930 onto an unskinnedarticle 1935. The image capturing device 1925 may be a camera, such as acharge-coupled device (CCD) camera. As the laser unit 1920 emits a linelaser onto the surface of the unskinned article 1935, the reflectedlight may be captured by the image capturing device 1925, which may beprocessed by a computer software to extract the dimension (e.g.,diameter, radius, circumference, axial length, and/or outer peripherallength) information.

Because of the jagged nature of the bare article due to the underlyingsquare or honeycomb matrix, it may be difficult to measure the dimension(e.g., diameter, radius, circumference, axial length, and/or outerperipheral length) at one point. In the present disclosure, a line laserprojected on the bare article in combination with a CCD camera 1925 forma profilometer that is able to discern the overall curvature of thearticle in addition to the peaks and valleys associated with the outerexposed matrix. In some embodiments, the laser unit 1920 and the CCDcamera 1925 may be positioned at four locations at 90 degree separationsaround the bare article. The laser units 1920 may be calibrated using aground cylinder of precise dimension (e.g., diameter) which is placed inthe measurement volume (e.g., on the platen 1515 where the unskinnedarticle 1935 is placed in FIG. 52).

Various algorithms may be developed to extract the article dimension(e.g., diameter, radius, circumference, axial length, and/or outerperipheral length) from the rough contour measurement, one of whichinvolves averaging the height of the peaks and valleys on the roughcontour over a series of 5 peaks centered on each laser. After thedistance between this average value is subtracted from the 180-degreeopposite lasers and the calibration factor is applied, the dimension(e.g., diameter) of the article along that axis will be known. Thismeasurement is simultaneously performed by the pair of laser units 1920and the CCD cameras 1925 on the orthogonal axis to provide twomeasurements of dimension (e.g., diameter) simultaneously. This setupmay be copied for as many as the number of simultaneous dimension (e.g.,diameter) measurements as desired. In some embodiments, the averagedimension (e.g., diameter) of the dimensions (e.g., diameters)s measuredat the multiple axes may be used as the dimension (e.g., diameter) ofthe unskinned article.

Because the lasers act at high speed (1 kHz), it is possible to measurethe dimension (e.g., diameter, radius, circumference, axial length,and/or outer peripheral length) of the incoming articles at a high ratethat would allow feed forward control to be possible. In addition, sincethe article will be passed through the fixed laser system, it ispossible to measure article dimension (e.g., diameter) variation alongthe length of the article or between articles. This could be valuable incontrolling manifold pressure and/or skinning speed within an article aswell as between articles. Process variation information may be obtainedfrom the real-time or near real-time dimension (e.g., diameter) data tounderstand the impact of non-uniformities of the article dimensions(e.g., diameters) on the process parameters, such as skin quality,pressure variation, etc.

In some embodiments, the dimension measuring laser devices 1560 may alsobe disposed adjacent the outlet of the skinning pipe 310 where theskinned articles move out of the skinning pipe 310. The dimensions(e.g., diameter, radius, circumference, axial length, and/or outerperipheral length) of the skinned articles may also be measured by thedimension measuring laser devices 1560. Alternatively or additionally,the defect monitoring and/or detecting laser devices 1555 may beconfigured to also measure the dimensions (e.g., diameters) of theskinned articles, in addition to or instead of monitoring and/ordetecting the defect. Combining the incoming unskinned article dimension(e.g., diameter) measurement with the skinned articles may also providereal-time or near real-time measurement of skin thickness since theincoming unskinned and skinned article dimensions (e.g., diameters) aremeasured continuously.

Referring to FIG. 52, the skinning control system 410 may receivesignals from the laser device 1560 and may calculate or determine thedimension (e.g., diameter, radius, circumference, axial length, and/orouter peripheral length) from the received signals. The received signalsmay include a signal indicating the distance between the laser head ofthe leaser unit 1920 and the lateral surface of the unskinned article1935. Because the distance between the two laser devices 1560 is known,the dimension (e.g., diameter) of the unskinned article 1935 may becalculated or determined based on the distance between the laser head ofthe laser unit 1920 and the lateral surface of the unskinned article1935.

FIG. 53 shows exemplary signals received from the laser devices 1560 fordetermining the dimension (e.g., diameter) of the unskinned articles.FIG. 53 shows line laser measurement of unskinned article contour beforethe unskinned article 1935 enters the skinning pipe 310. The x-axis(horizontal) is the distance in the width direction of the line laser(e.g., the circumferential direction of the unskinned article 1935). They-axis (vertical) is the relative distance from the laser head of thelaser unit 1920. The “0” position is at the laser head of the laserunit. Thus, the distance in the y-axis is negative. The jagged linemarked with “A” is the measurement signal obtained by the laser device1560. The line is jagged because the surface of the unskinned article1935 is not smooth (as it has not been coated with the skin). The linemarked with “B” is a curve used to fit the jagged line “A.”

The dimension (e.g., diameter) of the unskinned article 1935 may beestimated or calculated either from the curve fitted line “B” and/orfrom the jagged line “A.” For example, the average relative distancevalue (along the y-axis) of the curve fitted line “B” over a regionalong the x-axis, such as the entire region of [−20, 20] or a region of[−5, 5] in the x-axis, may be used to calculate the dimension (e.g.,diameter) of the unskinned article 1935. Another method that may be usedto calculate the dimension (e.g., diameter) is to take a region, e.g.,[−5, 5] in the x-axis, and calculate the average relative distance valueof the peaks and valleys within the selected region. The averagerelative distance may be used to further calculate the dimension (e.g.,diameter) of the unskinned article 1930.

FIG. 54 is an isometric view of the exemplary article feeding mechanism315. The article feeding mechanism 315 may include a centering mechanism1510. The centering mechanism 1510 may include a plurality of centeringdevices 1520. Although four centering devices 1520 are shown in FIG. 54,the centering mechanism 1510 may include any suitable number ofcentering devices 1520, such as, for example, one two, three, five, six,eight, etc.

Each centering device 1520 may include a centering actuator 1940, andone or more rollers 1945. Although FIG. 54 shows two rollers 1945 foreach centering device 1520, the centering device 1520 may include anysuitable number of rollers 1945, such as, for example, one, three, four,etc. The centering actuator 1940 may be stroke forward to center thearticle with respect to the central machine axis (e.g., the central axisof the skinning pipe 310).

The centering device 1520 may include at least one air knife 1950. Theair knife 1950 may be configured to blow air toward the platen 1515 toblow off any debris from the platen 1515 before an unskinned article isloaded onto the platen 1515. The air knife 1950 may also blow air towardthe unskinned article when the unskinned article is loaded onto theplaten 1515 to blow off debris from the unskinned article.

The article feeding mechanism 315 may include an alignment base 1955mounted on the lower carriage 1525. One or more force sensors 1960(e.g., at least one second force sensor 1960) may be disposed atsuitable locations in the article feeding mechanism 315 or on the lowercarriage 1525. The force sensors 1960 may be configured to measureforces (e.g., a second force) experienced by the lower carriage 1525during the skinning process. In some embodiments, three force sensors1960 may be used. Other number of force sensors 1960 may also be used,such as, for example, one, two, four, etc.

FIG. 55 is a schematic cross sectional view of the exemplary articlefeeding mechanism 315 shown in FIG. 54. The article feeding mechanism315 may include a flexure shaft 1965 and a spacer 1970. The flexureshaft 1965 may be disposed above the alignment base 1955 and below thespacer 1970. The spacer 1970 may be disposed below the platen 1515.

FIGS. 56A and 56B shows isometric views of the centering mechanism 1510.When an unskinned article is loaded on the platen 1515, the centeringactuator 1940 may only have limited movement toward the center of theplaten 1515 when centering the unskinned article. Thus, when thedimension (e.g., diameter) of the unskinned article is changed, e.g.,from 13 inches in diameter to 7 inches in diameter, the positions of thecentering actuator 1940 need to be adjusted accordingly. At least oneadjusting mechanism 1975 may be included in each centering device 1520.The adjusting mechanism 1975 may automatically adjust the position ofthe centering actuator 1940 (e.g., moves the centering actuator 1940closer to or away from the platen 1515 when the dimension of theunskinned article has changed). The adjusting mechanism 1975 may also bemanually operated to adjust the position of the centering actuator 1940.

FIGS. 56A and 56B show a manual adjustment configuration of theadjusting mechanism 1975. FIG. 56A shows the position of the centeringactuators 1940 for centering an article with a larger dimension (e.g.,13-inch diameter) and FIG. 56B shows the position of the centeringactuators 1940 for centering an article with a smaller dimension (e.g.,7-inch diameter). The adjusting mechanism 1975 may include a support1980 with at least one guide hole within its body. The centeringactuator 1940 may be mounted on one or more rods 1985. The adjustingmechanism 1975 may include a locating plate 1990 having a plurality ofholes, and a locating pin 1995 configured to engage with one of theplurality of holes on the locating plate 1990.

Referring to FIGS. 56A and 56B, the rods 1985, the centering actuator1940, and the locating plate 1990 may move together. The rods 1985 maybe inserted into the guide holes of the support 1980, and may slidealong the guide holes such that the position of the centering actuator1940 may be adjusted relative to the platen 1515. The locating plate1990 may be connected with the centering actuator 1940 and the rod 1985.The locating plate 1990 may be moved to adjust the position of thecentering actuator 1940 relative to the platen 1515. To secure thedesired position of the centering actuator 1940, the locating pin 1995may be inserted into one of the plurality of holes located on thelocating plate 1990 and a hole provided on a bracket 2000 that ismounted to the support 1980. The number of holes on the locating plate1990 may be designed based on the dimensions (e.g., diameters) of thearticles to be skinned. Incremental holes may be included in thelocating plate 1990 such that the position of the centering actuator1940 relative to the platen 1515 may be incrementally adjusted (e.g.,one inch at a time) to accommodate different dimensions (e.g.,diameters) of the articles.

FIGS. 57A and 57B show isometric views of the centering mechanism 1510.In this embodiment, the position of the centering actuator 1940 may beadjusted automatically by the adjusting mechanism 1975. Instead of usinglocating plate 1990, locating pin 1995, and the bracket 2000 to adjustthe position of the centering actuator 1940, the centering actuator1940, along with the rod 1985, may be driven by a motor 2005, such thatthe rod 1985 moves along the guide holes of the support 1980. The motor2005 may be coupled to the support 1980. In some embodiments, the motor2005 may be disposed within the support 1980, or may be mounted to thesupport 1980.

The centering actuator 1940 may be mounted to the rod 1985. The motor2005 may be controlled, e.g., by the skinning control system 410, tomove the rod 1985 along the guide holes within the support, therebyadjusting the position of the centering actuator 1940 relative to theplaten 1515. The automatic adjustment may save time and labor costassociated with manual adjustment. The motor 2005 may be controlled(e.g., by the skinning control system 410) to adjust the position of thecentering actuator 1940 incrementally (e.g., by 0.1 inch, 0.5 inch, 1inch, etc.) so that more precise adjustment may be achieved.

The centering mechanism 1510 of the present disclosure (e.g., shown inFIGS. 56A-57B) may enable precise article centering of crude articles,such as, for example, ceramic diesel substrates that may have relativelylarge shape variations when compared to an ideal cylinder. In someembodiments, when the articles to be skinned are in cylindrical shapes,the centering mechanism 1510 may include four quadrants, as shown inFIGS. 56A-57B, each quadrant including a centering actuator 1940 withtwo rollers 1945. This configuration may work well with quadrant shapedarticles, although it may also work well with articles of other shapes.

FIGS. 58A and 58B schematically show the article feeding mechanism 315with the flexure shaft 1965. FIG. 58A shows how the article feedingmechanism 315 works when the articles 2010 and 2015 are made perfectlycylindrical and have perfectly parallel surfaces. In such a situation,the articles may be perfectly aligned with the skinning pipe 310, andthe flexure shaft 1965 does not deflect or bend. FIG. 58B shows thesituation when the articles 2010 and 2015 are not perfectly cylindrical,or have parallelism errors in their surfaces. In such a situation, theflexure shaft 1965 may be deflectable. For example, the flexure shaft1965 may deflect or bend in a direction substantially perpendicular tothe center axis of the inner space of the skinning pipe 310. Thedeflection or bend of the flexure shaft 1965 may be within apredetermined range so that the bending or deflection does not becomepermanent. The flexure shaft 1965 may bend or deflect to compensate forthe misalignment between the articles and the skinning pipe 310, whichmay be caused by the parallelism errors or other reasons, therebyallowing the misaligned or out-of-tolerance articles to be pushedthrough the skinning pipe 310 without jamming.

The flexure shaft or flexure shaft assembly 1965 may include an upperplate 1967, a lower plate 1968, and a middle portion between the upperplate and the lower plate. In some embodiments, the upper plate 1967 andthe lower plate 1968 may not be parts of the flexure shaft 1965, but maybe connected to the flexure shaft 1965. In some embodiments, the upperplate 1967 and the lower plate 1968 are integrated with the middleportion to form the flexure shaft 1965. For discussion purposes, theupper plate 1967 and the lower plate 1968 are referred to as parts ofthe flexure shaft 1965.

FIG. 59 shows cross-sectional isometric view of the output deflectionplot of a Finite Element Analysis in which a force is applied to oneside of the flexure shaft 1965. In some embodiments, the flexure shaft1965 may be made of steel, having a diameter of about 0.5 inches, alength of about 2.5 inches, and corner radii of about 0.25 inches. Theresulting deflection may be about 0.6 mm of tilt when a force of 13pounds is applied at the location and direction shown in FIG. 59. Themaximum von Mises stress for this condition is 6400 psi, which is wellbelow the yield strength of common 1020 steel.

FIG. 60 schematically shows an enlarged view of the exemplary flexureshaft 1965 and associated elements. The article feeding mechanism 315may include one or more tilt limiters 2020 located adjacent the flexureshaft 1965. For example, the tilt limiters 2020 may be located betweenthe upper plate 1967 and the lower plate 1968 of the flexure shaft 1965.In some embodiments, the tilt limiters 2020 may be mounted on the lowerplate 1968. The tilt limiters 2020 may be configured to limit an amountof deflection of the flexure shaft 1965, thereby preventing the flexureshaft 1965 from being over flexed and yielded (e.g., permanentlydeformed) during a machine crash, which may occur when, for example, themotion of the lower machine axis (e.g., including the lower carriage1525 and the article feeding mechanism 315) is programmed wrong and anunexpected load occurs through the article feeding mechanism to thelower carriage 1525.

Radial and axial gaps may be created in the assembly to allow theflexure shaft 1965 assembly (e.g., including the upper plate 1967 andthe lower plate 1968) to relatively freely move in the tip/tilt andradial directions. In some embodiments, the magnitude of these gaps maybe less than 1 mm, such as, for example, 0.5 mm, 0.6 mm, 0.8 mm, etc.Each tilt limiter 2020 may include an axial stop 2025 that limits theaxial deflection of the flexure shaft 1965. The tilt limiter 2020 mayinclude a radial stop 2030 that limits the radial deflection of theflexure shaft 1965. The tilt limiter 2020 may include counterbores 2040,in which rubber pads may be disposed for dampening the natural vibrationof the flexure shaft 1965 assembly.

FIG. 61 is a schematic diagram of the exemplary article feedingmechanism 315. A spacer 2035 is placed off-axis between two articles2010 and 2015 to simulate the condition of an article being fed throughthe skinning pipe 310 with excessive parallelism errors in the surfaces.

FIG. 62 shows the dimension of the spacer 2035. The spacer 2035 is 1.99mm thick. The spacer 2035 creates a radial error of 1.1 mm. The articles2010 and 2015 have a twelve-inch diameter and are six inches long.

FIG. 63 shows a plot of maximum axial push force measured by the forcesensors 1960 of the article feeding mechanism 315. The maximum force isplotted for each successive article. As shown, the largest forceexperienced was approximately 250 pounds. The machine components arecapable of intermittently experiencing approximately double these forces(e.g., about 500 pounds) without undue wear or failure. If the flexureshaft 1965 was not used, a jamming would have occurred which would haveforced the process to be shut down and unusual machine maintenance wouldhave been required.

The compliant article feeding mechanism 315 that includes the flexureshaft 1965 enables out-of-balance articles to move through the skinningpipe 310 without jamming. The compliant article feeding mechanism 315may help articles that have parallelism errors to engage properly andmaintain the forces in an axial direction. The compliant article feedingmechanism 315 may also enable radial compliance after a lower articlehas been centrally and precisely engaged with an upper article locatedabove the lower article within the skinning pipe 310. The compliantarticle feeding mechanism 315 may enable the article to be delivered tothe centerline of the skinning pipe 310 with radial precision (submicronrepeatability). Precise alignment improves the skin thicknessuniformity, reduces wear of the skinning pipe 310 caused by rubbing.Rubbing of the misaligned articles against the skinning pipe 310 maycause debris to fall off, affecting the quality of skins. Misalignmentbetween the articles and the skinning pipe 310 may reduce the feedingforce. With precise alignment, the speed of skinning may be increased,meaning that articles may be delivered at a high speed into the skinningpipe 310. Precise alignment also minimizes dead cells caused by twoconsecutive articles being radially eccentric to each other.

FIG. 64 is an isometric view of the exemplary loading robot 1565. Theloading robot 1565 may include the vacuum chuck 1571, which is alsoshown in FIG. 26. The vacuum chuck 1571 may be configured to hold andlift an unskinned article using vacuum pressure or vacuum force, andtransport the unskinned article onto the article feeding mechanism 315(e.g., the platen 1515). The vacuum chuck 1571 may be similar to thevacuum chuck 1550 mounted to the upper carriage 1525, as shown in, e.g.,FIG. 26. The loading vacuum chuck 1571 may be similar to the vacuumchuck 1550, and may be configured to generate independently controlledmultiple vacuum zones (e.g., two zones).

The vacuum chuck 1571 may pick up (e.g., hold and lift) a single articlewith a single spacer located at the bottom surface of the article,whether it is a donut shaped spacer 1600 or a donut hole shaped spacer1605. In some embodiments, when the vacuum chuck 1571 is a dual-zonevacuum chuck, two vacuum valves 2045 may be located on the loading robot1565 to open and close vacuum pressure communication to the two zones ofthe vacuum chuck 1571. The valves 2045 may be connected with the vacuumchuck 1571 through connection hoses 2050. Similar to the vacuum chuck1550, the vacuum chuck 1571 mounted on the loading robot 1565 may bechanged for a larger or smaller vacuum chuck 1571 when the sizes (ordimensions) of the articles are changed (e.g., from seven-inch diameterarticles to thirteen-inch diameter articles).

FIG. 65 is an isometric view of the exemplary unloading robot 1566. Theunloading robot 1566 may include at least one arm 1570 (e.g., two ormore arms 1570), which are also shown in FIG. 26. The arms 1570 may beconfigured to receive a skinned article from the vacuum chuck 1550,transport it and place it onto a conveyance system for furtherprocessing. The arms 1570 may be adjustable arms 1570 configured tosupport articles with different dimensions (e.g., diameters) withouttouching the edge of the wet skin (flowable mixture) coated to thearticle. For example, the distance between the two arms 1570 may beadjusted to fit the skinned articles of different sizes. The arms 1570may support the bottom surface of the skinned article. The unloadingrobot 1566 may also include a sensor 2055 configured to detect thepresence of an article in the arms 1570. The sensor 2055 may be mountedon the arms 1570, or at any other suitable locations on the unloadingrobot 1566. The sensor 2055 may use any suitable technology fordetecting the presence of the article, such as, for example, opticaltechnology, electro-magnetic technology, thermo technology, etc.

Force Sensors and Motion Controls

As shown in FIGS. 27A-27E, in the skinning system 300, two axes worktogether to keep the articles moving through the skinning pipe 310 toreceive the flowable mixture (e.g., to be skinned). The two axes includean upper axis and a lower axis. The upper axis may include the uppercarriage 1540 and the vacuum system 320 (including the vacuum chuck1550) mounted to the upper carriage 1540, which are shown in, e.g., FIG.26. The lower axis may include the lower carriage 1525 and the articlefeeding mechanism 315, which are also shown in, e.g., FIG. 26.

Force sensors may be included in the skinning system 300 and configuredto measure forces that may be used by the skinning control system 410 tocontrol the motions of the two axes so that the articles are movedthrough the skinning pipe 310 at a substantially constant speed. Forcesensors may measure the forces between the upper carriage 1540 and thelower carriage 1525 (or between the vacuum system 320 mounted to theupper carriage 1540 and the article feeding mechanism 315 mounted to thelower carriage 1525), and the measured forces may be used by theskinning control system 410 to determine when a lower article hasengaged with an upper article. When the skinning control system 400determines that two articles have engaged with one another, thecontroller may begin moving the two axes at the same speed. Once thismating of the upper and lower axes has completed, the upper axis may befree to disengage and move upward at a greater speed than the lower axisto a position where the article (e.g., skinned article) it carries maybe unloaded.

FIG. 66 is a schematic diagram showing the exemplary skinning system 300with force sensors. As shown in FIG. 66, one or more force sensors 1645may be disposed at suitable locations within the upper axis, forexample, mounted to the upper carriage 1540, to the vacuum chuck 1550,or other elements of the vacuum system 320, as shown in FIGS. 29A-29Band 31A-31B. In some embodiments, as shown in FIGS. 31A and 31B, threeforce sensors 1645 may be used, although other suitable numbers of forcesensors 1645 may also be used. Two force sensors 1645 are shown in theschematic diagram for illustrative purposes.

The force sensors 1645 may measure forces experienced by the upper axis,for example, when the articles 2010 and 2015 engage with one another bythe push of the lower axis. The skinning system 300 may include one ormore force sensors 1960 disposed at suitable locations within the loweraxis, for example, mounted to the lower carriage 1525, to the flexureshaft 1965, or any other elements included in the lower axis. In someembodiments, three force sensors 1960 may be used, although any othersuitable number of force sensors 1960 may also be used. Two forcesensors 1960 are shown in the schematic diagram for illustrativepurposes.

The force sensors 1960 may or may not be similar to the force sensors1645. The force sensors 1960 may be configured to measure forcesexperienced by the lower axis, such as, for example, when the articles2010 and 2015 engage with one another while the lower axis pushes thelower article 2015 into the skinning pipe 310. The forces measured bythe force sensors 1645 and the force sensors 1960 may be used by theskinning control system 410 to determine when the lower and upper axesshould move at the same speed, when the upper axis can disengage withthe lower axis (e.g., when the upper carriage 1540 can move up at ahigher speed to unload a skinned article 2010), and/or when the loweraxis can disengage with the upper axis (e.g., when the lower carriage1525 can stop pushing and move downward to receive a new unskinnedarticle). That is, the timing of the hand-off between the two axes maybe determined based on the forces measured by the force sensors 1645 and1960.

FIGS. 67A-67E show the motion of the upper and lower axes of theskinning system 310, and FIG. 67F shows the status of various elementsincluded in the skinning system 310. FIGS. 67A-67E are similar to FIGS.27A-27E. Therefore, the descriptions of FIGS. 67A-67E are similar tothose of FIGS. 27A-27E. FIG. 67F show the status of the elements in theskinning system 300 in which a dual-zone vacuum system is used, such asone shown in FIG. 28. The dual-zone vacuum system is only used forillustrative purposes, and the skinning system 300 may use a vacuumsystem with one zone or more than two zones.

As shown in FIG. 67F, at a first stage (stage “5A” in FIG. 67F, prior toloading an unskinned article, the status of the centering devices 1520(“Centering Extend” in FIG. 67F) may be “off” (e.g., not activated ornot turned on), the status of the side vacuum zone 1595 (“Vac Outer” inFIG. 67F) may be “on” (e.g., activated or turned on), and status of thecenter vacuum zone 1590 (“Vac Inner” in FIG. 67F) may be “on.” The lowercarriage 1525 (“Bottom Stage” in FIG. 67F) may move rapidly downward toa loading position to receive an unskinned article, and the uppercarriage 1540 (“Upper Stage” in FIG. 67F) may move upward at apredetermined process speed. The air knife 1950 may be “on” or “off”.

Referring to FIG. 67F, at a second stage (stage “1” in FIG. 67F), whenan unskinned article is loaded onto the article feeding mechanism 315,the status of the centering devices 1520 may be “of” and the status ofthe center vacuum zone 1590 and the side vacuum zone 1595 may both be“on.” The lower carriage 1525 may stop at the loading position toreceive an unskinned article to be loaded by the loading robot 1565. Theupper carriage 1540 may move upward at the process speed. The status ofthe air knife 1950 may be “off.”

Referring to FIG. 67F, at a third stage (stage “1A” in FIG. 67F), afterreceiving the unskinned article, the lower carriage 1525 may move upwardtoward the skinning pipe 310 to insert (or push) the unskinned article(referred to as a lower article for the purpose of discussion of FIG.67F) into the skinning pipe 310. There may already be at least onearticle (referred to as an upper article for the purpose of discussionof FIG. 67F) in the skinning pipe 310. During the process when the lowerarticle is pushed into the skinning pipe 310 to be engaged with theupper article, the status of the centering devices 1520 may be “on.” Thestatus of the center vacuum zone 1590 and the side vacuum zone 1595 maybe “on.” The lower carriage 1525 may move rapidly upward, and the uppercarriage 1540 may move upward at the process speed. The status of theair knife 1950 may be “off”

Referring to FIG. 67F, at a fourth stage (stage “2” in FIG. 67F), afterthe lower article engages with the upper article, the two may movetogether. The status of the centering devices 1520 may be “on” or “off”the status of the center vacuum zone 1590 and the side vacuum zone 1595may be “on.” The lower carriage 1525 may move upward at the processspeed and the upper carriage 1540 may also move upward at the processspeed. In this combined movement stage, the upper carriage 1540 and thelower carriage 1525 move upward at the same process speed. The status ofthe air knife 1950 may be “off.”

Referring to FIG. 67F, at a fifth stage (stage “2A” in FIG. 67F), one ofthe vacuum zone may be turned off. At this stage, the status of thecentering devices 1520 may be “off.” The status of the side vacuum zone1595 may be “on,” and the status of the center vacuum zone 1590 may be“off” Depending on the sequence of the donut shaped and donut holeshaped spacers used, in some embodiments, instead of turning off thecenter vacuum zone 1590, the side vacuum zone 1595 may be turned off andthe center vacuum zone 1590 may remain “on.” That is, the status of thecenter vacuum zone 1590 and the side vacuum zone 1595 shown in FIG. 67Fmay be switched. At this stage, the lower carriage 1525 may move upwardat the process speed. After turning off one vacuum zone, the uppercarriage 1540 may disengage with the lower carriage 1525. The upperarticle held by the upper carriage 1540 may disengage with the lowerarticle, which was held by the other vacuum zone that is now turned off.The status of the air knife 1950 may be “off.”

Referring to FIG. 67F, at a sixth stage (stage “3” in FIG. 67F), theupper article may be moved rapidly upward by the upper carriage 1540 forunloading. The status of the centering devices 1520 may be “off” Thestatus of the side vacuum zone 1595 may be “on,” and the status of thecenter vacuum zone 1590 may be “off” The lower carriage 1525 may moveupward at the process speed, and the upper carriage 1540 may move upwardrapidly for unloading the skinned article. The status of the air knife1950 may be “off”

Referring to FIG. 67F, at a seventh stage (stage “3A” in FIG. 67F), theupper article (e.g., skinned article) may be unloaded. At this stage,the status of the centering devices 1520 may be “off.” The status of thecenter vacuum zone 1590 and the side vacuum zone 1595 may both be “off”The lower carriage 1525 may move upward at the process speed, and theupper carriage 1540 may be stationary such that the skinned upperarticle may be unloaded by the unloading 1566. The status of the airknife 1950 may be “off.”

Referring to FIG. 67F, at an eighth stage (stage “4” in FIG. 67F), inwhich the upper carriage 1540 re-engages with the articles moving out ofthe skinning pipe 310 after the skinned article has been unloaded by theunloading robot 1566. The status of the centering devices 1520 is “off”The status of the side vacuum zone 1595 and the center vacuum zone 1590may be “off” The lower carriage 1525 may move upward at the processspeed, and the upper carriage 1540 may rapidly move downward toward theskinning pipe 310. The status of the air knife 1950 may be “off”

Referring to FIG. 67F, at a ninth stage (stage “4A” in FIG. 67F), thecenter vacuum zone 1590 and the side vacuum zone 1595 may be turned on.The status of the centering devices 1520 may be “off” The status of thecenter vacuum zone 1590 and the side vacuum zone 1595 may be “on.” Thelower carriage 1525 may move upward at the process speed. The uppercarriage 1540, after engaging with the article moving out of theskinning pipe 310 (e.g., by holding the article with the vacuum force),may move upward at the process speed. The status of the air knife 1950may be “off”

Referring to FIG. 67F, at a tenth stage (stage “5” in FIG. 67F), thelower carriage 1525 (or the lower axis) may be disengaged from thearticle in the skinning pipe 310. The status of the centering devices1520 may be “off.” The status of the center vacuum zone 1590 and theside vacuum zone 1595 may be “on.” The lower carriage 1525 may moverapidly downward to the loading position to receive another unskinnedarticle. The upper carriage 1540 may move upward at the process speed.The status of the air knife 1950 may be “on.”

Controls of Skinning System

Various processes disclosed herein may be performed by the controlsystem 400. Controls of the skinning system 300 may also involvecontrols of the mixture delivery system 200. Although for discussionconvenience, it is described throughout the disclosure that someprocesses may be performed by the mixture control system 405, and someprocesses may be performed by the skinning control system 410, eithermixture control system 405 and skinning control system 410 or acombination of these control systems may perform any process forcontrolling the skinning system 300 and/or the mixture delivery system200.

FIG. 68 shows a schematic diagram showing the skinning control system410. FIG. 68 schematically shows the mixture delivery system 200 and theskinning system 300. For illustrative purposes, only some elements ofthe mixture delivery system 200 and the skinning system 300 are shown.The mixture delivery system 200 and the skinning system 300 may includeother elements or features disclosed in the present disclosure inaddition to or instead of the elements shown in FIG. 68. The mixturedelivery system 200 and the skinning system 300 may not include all ofthe elements shown in FIG. 68.

As shown in FIG. 68, the mixture delivery system 200 may include themixer 220 configured to mix a fluid and a dry material to produce aflowable mixture, the storage device 225 configured to store theflowable mixture, the pump 235 configured to pump the flowable mixtureto the delivery line 240 leading to the skinning system 300. The flow ofthe mixture to the skinning system 300 may be controlled by the deliveryvalve 245. The mixture delivery system 200 may include the recirculationline 260 configured to recirculate the flowable mixture when, forexample, the delivery valve 245 is closed to shut down the flow of themixture to the skinning system 300. The valve 275 may control the flowwithin the recirculation line 260. The recirculation line 260 may beconnected with the storage device 225. The flowable mixture redirectedfrom the main delivery line 240 may be returned to the storage devicethrough the recirculation line 260. Additional and/or alternativecomponents or devices that may be included in the mixture deliverysystem 200 have been discussed above in connection with other figures.

As shown in FIG. 68, the skinning system 300 may include the elementsshown in previous figures that have already been discussed above. Theskinning control system 410, which may be part of the control system 400shown in FIG. 1, may be connected with the skinning system 300 and maybe configured to control the operations of the skinning system 300. Theskinning control system may include a processor 2060, a memory 2065, anda communication unit 2070. The communication unit 2070 may be adedicated communication unit for the skinning control system 410, or maybe the same as or similar to the communication unit 425 included in thecontrol system 400, as shown in FIG. 1. In some embodiments, thecommunication unit 2070 may be part of the communication unit 425 shownin FIG. 1.

The processor 2060 and the memory 2065 may be dedicated processor andmemory for the skinning control system 410, or may be the same as orsimilar to the processor 415 and memory 420 shown in FIG. 1. In someembodiments, the processor 2060 and memory 2065 may be part of theprocessor 415 and memory 420 shown in FIG. 1. In some embodiments, theskinning control system 410 may be implemented as software, programs,computer executable instructions or codes, which may be encoded in thememory 420 shown in FIG. 1 or a tangible, nontransitorycomputer-readable medium, such as a hard-disk, a compact disc, a flashmemory, etc. The communication unit 450 may communicate with theskinning system 300 through the network 430. The communication unit 2070may also communicate with the mixture control system 405 via acommunication line or network 2075, which may include a wired orwireless network. For example, the skinning control system 410 maycommunicate with various components included in the mixture deliverysystem 300 directly or through the mixture control system 405. Theskinning control system 410 may receive data or signals from variouscomponents included in the mixture delivery system 300 and may transmitcontrol signals to the various components. The mixture control system405 may be part of the control system 400 and may be configured tocontrol the mixture delivery system 200.

The processor 2060 may be any suitable computer processor that includescomputing capabilities, such as, for example, a central processing unit(CPU), a signal processor, etc. The memory 2065 may be any suitablememory configured to store programs, instructions, and/or codes, whichmay be executed by the processor 2060. The memory 2065 may be anon-transitory or tangible random access memory (RAM), a read onlymemory (ROM), a flash memory, etc. The processor 2060 may read theinstructions and/or codes from the memory 2065 and execute theinstructions and/or codes to run programs that perform variousfunctions, such as the methods or processes disclosed herein.

FIG. 69 is a flowchart illustrating an exemplary method (or process,operation) 2100 of the skinning control system 300. The skinning system300 may operate together with the mixture delivery system 200. Thus,certain processes involving the mixture delivery system 200 are alsoincluded in FIG. 69.

In the exemplary method 2100, for illustrative purposes, the mixturedelivery system 200 is assumed to include a recirculation line 260 asshown in FIG. 68. In the method 2100, first, the mixture delivery system200 may be started to run in a recirculation mode using therecirculation line 260 (block 2105, also referred to as stage “X” inFIG. 69). The pump 235 may advance the flowable mixture produced by themixer 220 to the delivery line 240. The delivery valve 245, which may bea two-way valve, may close one path to prevent the flow to the skinningsystem 300, and open the other path to allow the mixture to flow intothe recirculation line 260. The flowable mixture may be continuouslyrecirculated using the recirculation line 260 without being delivered tothe skinning system 300. A return pressure control may be activated. Thereturn pressure may refer to the pressure within the recirculation line260. The return pressure set point (e.g., target return pressure) may bedetermined, and the position (e.g., opening) of the return valve 275 maybe determined.

Return Pressure Set Point

Determining the pressure in the recirculation line 260 just before theskinning process starts may facilitate speeding up the start-up of theskinning process and reduce or eliminate any pressure related defects onthe final skinned part during start-up. The flowable mixture returnpressure set point acts (or simply return pressure set point) as aninitial condition to the skinning pipe pressure control scheme discussedbelow. The return pressure set point is the desired or target returnpressure in the recirculation line 260. Based on the target skinningspeed, the return pressure set point may be determined using therelation shown in FIG. 71, which shows a sample plot of return pressureversus skinning speed, showing the impact of the skinning speed on thereturn pressure. The relationship shown in FIG. 71 may be represented bythe following equation (C-1):

Return Pressure Set Point=4.1527*(Skinning speed inmm/sec)+28.353  (C-1)

Equation (C-1) is an example equation reflecting the relationshipbetween the return pressure set point and the skinning speed. Theparameters 4.1527 and 28.353 are exemplary only. Other parameters may beused depending on the system configurations. The return pressure setpoint determined based on equation (C-1) is for a nominal viscosity ofabout 40000 centipoise (cP). The relationship or function described byequation (C-1) may depend on the composition of the flowable mixtureand/or the nominal viscosity of the flowable mixture. After the returnpressure set point is determined to match the desired or target skinningspeed, the return pressure control may be activated. Details of thereturn pressure control are described below along with the skinningpressure control scheme. The position (e.g., opening) of the returnvalve 275 may be adjusted before activating the return pressure control,since if the return valve 275 is completely open, there may not beenough back pressure for the control to maintain the return pressure.The return pressure control may be useful for the skinning pipe pressurecontrol, such as one shown in FIG. 72.

For the skinning pipe pressure control scheme shown in FIG. 74, thereturn pressure control may be replaced with the flowable mixture flowrate control. Approaches similar to those discussed above in connectionwith equation (C-1) and FIG. 71 may be taken to determine the desiredflow rate set point before the skinning process starts and requestsflowable mixture from the mixture delivery system 200. The requirementon the return pressure set point may not be stringent. If the valueobtained is close to the desired operating regime (e.g., if the returnpressure is within an acceptable range of the desired return pressureset point), it still helps with the speeding up of the start-up of theskinning process. Also, once the skinning pipe pressure control schemeis activated, the control scheme may automatically adjust the returnpressure to control the skinning pipe pressure. Some embodiments of themixture delivery system 200 may not include the recirculation line 260.In such embodiments, the return pressure control may not be needed.

Skinning Process Start-Up Control

Referring to FIG. 69, details pertaining to sections referred to as “Y”in the flowchart are discussed below. The skinning process is initiatedby starting receiving the flowable mixture from the mixture deliverysystem (block 2110). This may be done by the control system 400 (e.g.,the mixture control system 405) sending a signal to the delivery valve245 to adjust its position to direct the flowable mixture to theskinning system 300. The return valve 275 may be closed to shut off therecirculation line 260 and provide enough back pressure to the skinningsystem 300 (e.g., the manifold 305 and the skinning pipe 310), so as toattain the desired skinning pipe pressure needed to obtain quality skin.The return valve 275 need not be completely closed and may also bepartially closed as long as enough back pressure is available to attainthe desired skinning pipe pressure at the exit of the manifold 305(e.g., at a point before the flowable mixture flows into the holes ofthe skinning pipe 310). The pressure of the flowable mixture at the exitof the manifold 305 or the inlet (which receives the flowable mixture)to the skinning pipe 310 (which may also be referred to as unipipepressure, skinning pipe pressure, pressure of the skinning pipe, orpressure of the unipipe) may provide information regarding whether thereis enough flowable mixture present in the manifold 305 to apply skin(e.g., flowable mixture) onto the article. Until the skinning pipepressure reaches a threshold value (which may be referred to as astart-up pressure in FIG. 69), the skinning process may not start. Thisenables significant reduction of defects during the start-up of theskinning process, such as “fast flow” defects (e.g., excessive flow ofmixture or skin on certain sections of the article) and “starvation”defects (e.g., lack of sufficient flowable mixture or skin on thearticle or partial application of the flowable mixture on the article).The start-up pressure may be a function of the weight of the part, asshown in equation (C-2):

Start-up Pressure=Ψ(weight of the article)  (C-2)

One example of the function, Ψ(.) may be defined as:

Start-up Pressure=4.2(article length>4 inches) or 3(article length≦4inches)  (C-3)

Equation (C-3) uses the article length as a parameter. The length of thearticle could be used as a surrogate measurement for the weight if thedimension (e.g., diameter) of the article does not change. If thedimension (e.g., diameter) changes, using the article length as aparameter for determining the start-up pressure may not be accurate,because if a higher pressure is used for a lighter article, then thereis a possibility of flowable mixture penetrating between articlescausing the articles to skew. This article skew may result in a skindefect around the article. In situations where the dimension (e.g.,diameter) may change, it may be desirable to use equation (C-2).

Referring to FIG. 69, the skinning control system 410 may determinewhether the skinning pipe pressure has reached or exceeded the start-uppressure (block 2115). If the skinning control system 410 determinesthat the skinning pipe pressure has not reached or exceeded the start-uppressure (No, block 2115), the skinning control system 410 may continuemeasuring and monitoring the skinning pipe pressure until the skinningpipe pressure has reached or exceeded the start-up pressure. If theskinning control system 410 determines that the skinning pipe pressurereaches or exceeds the start-up pressure (Yes, block 2115), the skinningprocess starts (block 2120). At this time, skinning articles may notstart.

The skinning control system 410 may determine whether the skinning pipepressure is less than a predetermined threshold skinning pipe pressure(e.g., 1 psi) (block 2125). The predetermined threshold skinning pipepressure may vary depending on the system configuration, and may beobtained via tests and experiments. Other suitable threshold pressure,e.g., 1.5 psi, 2 psi, 0.95 psi, etc., may also be used. Thisdetermination at block 2125 may only need to be performed once after thestart-up.

If the skinning control system 410 determines that the skinning pipepressure is less than the predetermined threshold skinning pipe pressure(e.g., if <1 psi) (Yes, block 2125), the skinning control system 410 mayactivate a start-up control (block 2130), which is discussed below indetails. The skinning control system 410 may also activate a skinningpipe pressure control (block 2135). If the skinning control system 410determines that the skinning pipe pressure is not less than thepredetermined threshold skinning pipe pressure (e.g., if ≧1 psi) (No,block 2125), the skinning control system 410 may not activate thestart-up control (e.g., skip block 2130), and may instead activate askinning pipe pressure control (block 2135). The start-up control andthe skinning pipe pressure control are discussed below.

Referring to FIG. 69, after the skinning pipe pressure control isactivated (block 2135), the skinning control system 410 may startskinning articles (block 2140) by sending a signal to the skinningsystem 300 to start or activate various components, such that the lowercarriage 1525, the upper carriage 1540, the loading robot 1565, and theunloading robot 1566, to transport the unskinned articles into theskinning pipe 310 and transport skinned articles out of the skinningpipe 310.

The skinning system 300 may use the laser devices 1555 to monitor and/ordetect presence of defects on the skinned articles. The skinning controlsystem 410 may determine whether a defect is present on the skin of theskinned article, and/or whether it has been detected (e.g., based onsignals received from the laser devices 1555) (block 2145). If theskinning control system 410 determines that no defect is detected (No,block 2145), the skinning control system 410 may determine whether theskinning process should be terminated or paused (block 2150). If theskinning control system 410 determines that the skinning process shouldnot be terminated or paused (No, block 2150), the skinning system 300may continue to skin articles (e.g., continues block 2140). If theskinning control system 410 determines that a defect has been detected(Yes, block 2145), the process may continue to operation “A,” thedetails of which are shown in FIG. 70.

If the skinning control system 410 determines that the skinning processshould be terminated or paused (Yes, block 2150), the skinning controlsystem 410 may terminate or pause the skinning process (block 2155). Toterminate or pause the skinning process, the skinning control system 410may send control signals to various components included in the skinningsystem 300 to deactivate them. In addition, the skinning control system410 may communicate with the mixture control system 405, such that themixture control system 405 may send control signals to variouscomponents included in the mixture delivery system 200 to deactivatethem so that the flowable mixture is no longer delivered to the skinningsystem 300. For example, the mixture control system 405 may send acontrol signal to the delivery valve 245 to adjust the position of thedelivery valve 245 to prevent flowable mixture from flowing to theskinning system 300. The mixture control system 405 may send a controlsignal to the return valve 275 to open the return valve 275, therebyallowing the flowable mixture to be recirculated within therecirculation line 260. The skinning control system 410 may deactivatethe skinning pipe pressure control, which is discussed in detail below.The return pressure control may be activated to control the returnpressure within the recirculation line 260.

FIG. 70 is a flowchart illustrating exemplary operations that may beincluded in the method 2100 shown in FIG. 69. Continuing from “A” inFIG. 69, after determining that a defect has been detected, the skinningcontrol system 410 may determine the type of defect (block 2160). Thedefect may be a fast flow type defect, a starvation type defect, a pitdefect, a pock defect, a ring defect, etc. The fast flow type defect andthe starvation type defect may be related to the skinning pipe pressure.The skinning control system 410 may determine whether the defect isrelated to the skinning pipe pressure (block 2165). When the skinningcontrol system 410 determines that the defect is a pressure relateddefect (Yes, block 2165), the skinning control system 410 may adjust theskinning pipe pressure set point (block 2170), and the process mayproceed to “B” in FIG. 69.

When the skinning control system 410 determines that the defect is not apressure related defect (No, block 2165), the skinning control system410 may determine whether the defect is a pit and/or pock (block 2175).When the skinning control system 410 determines that the defect is a pitand/or pock (Yes, block 2175), the skinning control system 410 may checkthe density of the flowable mixture and adjust the density (e.g., byadjusting a mixer speed) if the density is outside the control limits(block 2180). The process may proceed to “C” in FIG. 69. When theskinning control system 410 determines that the defect is not a pit or apock (No, block 2175), the process may proceed to “C” in FIG. 69.

Start-Up Control Strategy

After starting the skinning process, if the skinning speed ramps quickly(e.g., in about 3-4 seconds) to the target skinning speed, the suddenchange in skinning speed from 0 mm/sec to the target speed may cause achange in the skinning pipe pressure, which may increase for slowertarget speeds (e.g., <5 mm/sec) and decrease for faster target speeds(e.g., >5 mm/sec). The 5 mm/second is a predetermined skinning speedthreshold, and may vary depending on the system configurations. Thepredetermined skinning speed threshold may be determined based on testsor experiments. The skinning pipe pressure change in the relatedtransients may last for about 3-4 articles during which time, there maybe a potential of getting pressure related defects (e.g., fast flow orstarvation) on the final skinned article. To significantly reduce thesedefects, the pressure related process transients need to be shortened sothat the skinning process reaches steady state sooner. Two differentcontrol solutions, discussed below, have been developed to address thisissue.

Start-Up Control Solution 1

This control solution depends on the target skinning speed. As mentionedabove, if the target skinning speed is less than the predeterminedthreshold value (e.g., less than 5 mm/sec, where 5 mm/sec is thepredetermine threshold value), the skinning pipe pressure may increaseas soon as the skinning process starts. For target skinning speeds ofgreater than the predetermined threshold value (e.g., greater than 5mm/sec), the skinning pipe pressure may decrease with the start of theskinning process.

For the first case (target skinning speed less than 5 mm/sec), beforethe start of the skinning process, the pressure relief system 1755 shownin FIGS. 38-41, 43, and 44 may be used to boost or increase the skinningpipe pressure (hence pressure relief system may also be referred to as apressure boost system 1755 or pressure adjustment system 1755). As shownin FIGS. 38-41, 43, and 44, the pressure boost system 1755 may include aring (e.g., a lower ring 1720) disposed adjacent or close to theskinning pipe 310. The lower ring 1720 may be moved up and down by theactuation of an actuator, such as, for example, the air cylinder typepressure release actuators 1760 and/or the electrical servo drivenactuator 1815 (e.g., ball screw actuator 1815). When the lower ring 1720moves up and down along the skinning pipe 310, it may change the volumeof the space 1810 (and hence the total volume of the internal passageswithin the manifold 305) available for the flowable mixture to flow tothe skinning pipe 310. Changing the volume of the flowable mixture mayaffect the pressure of the flowable mixture before the flowable mixtureflows to the inner space of the skinning pipe 310 (e.g., the skinningpipe pressure).

In some embodiments, the pressure boost system 1755 may be configuredsuch that when the lower ring 1720 moves up to an upper position, thevolume of the space 1810 is reduced (thus the skinning pipe pressure isincreased), and when the lower ring 1720 moves down to a lower position,the volume of the space 1810 is increased (thus the skinning pipepressure is reduced). In some embodiments, the pressure boost system1755 may be designed such that when the lower ring 1720 moves to theupper position, the volume of the space 1810 is increased and theskinning pipe pressure is reduced, and when the lower ring 1720 moves tothe lower position, the volume of the space 1810 is reduced and theskinning pipe pressure is increased.

For illustrative purposes, the activation of the pressure boost system1755 may be defined to be the case where the lower ring 1720 is in theupper position (hence the volume is reduced, and the skinning pipepressure is boosted or increased). Thus, deactivating the pressure boostsystem 1755 refers to the status where the lower ring is at a lowerposition, which results in an increased volume of the space 1810 for theflowable mixture and reduced skinning pipe pressure. The definition ofactivation and deactivation of the pressure boost system 1755 may bedefined in an opposite manner. In some embodiments, there may be threepositions for the lower ring 1720, an upper position where the skinningpipe pressure is increased, a neutral position where the skinning pipepressure is neither increased nor decreased, and a lower position wherethe skinning pipe pressure is decreased. When an electrical servo drivenmotor (e.g., the ball screw actuator 1815 shown in FIG. 44) is used, thelower ring 1720 may be finely adjusted to incrementally change theskinning pipe pressure.

As the skinning pipe pressure starts to increase, the pressure boostsystem 1755 may be deactivated. The lower ring 1720 may move down,increasing the volume of the space 1810 adjacent the skinning pipe 310that is available for the flowable mixture to flow, which in turndecreases the skinning pipe pressure. Once the skinning process reachessteady-state, the skinning pipe pressure control may be activated. Theskinning process could be run with the pressure boost system 1755 inthis current state (deactivated state) until the end of the campaign.For the case when the target skinning speed is greater than 5 mm/sec,before the start of the skinning process, the pressure boost system mustbe deactivated (the lower ring 1720 is in the lower position). As theskinning pipe pressure starts to decrease, the pressure boost system1755 is activated to cause the lower ring 1720 to move up. Since thesame amount of skin material (flowable mixture) now has reduced volumeor space than before, the skinning pipe pressure increases, therebyproviding enough flowable mixture pressure to obtain good quality skinon the articles. Once the skinning process reaches steady-state, theskinning pipe pressure control (described below) may be activated. Theskinning process may be run with the pressure boost system 1755 in thecurrent state (activated state) until the end of the campaign.

Start-Up Control Solution 2

This control solution option may be valid only for the case when thetarget skinning speed is greater than 5 mm/sec. In this case, theskinning pipe pressure decreases as soon as the skinning process starts.In this control solution, as the skinning process starts, instead oframping the skinning speed from 0 mm/sec to the target skinning speed(e.g., 8 mm/sec) in about 3-4 seconds, the skinning control system 410may increase the skinning speed incrementally in a plurality of stages,e.g., at a first stage, skinning the first article at 3 mm/sec, at asecond stage, skinning the second article at 5 mm/sec, and at the thirdstage, skinning the third article at the target skinning speed. Thisway, the mixture delivery process has sufficient time to catch up withthe skinning speed and the skinning pipe pressure does not decreaseduring start-up. With this control method, the flowable mixture returnpressure set point also needs to be changed for the first 3 articles asthe return pressure set point is a function of the skinning speed, asdescribed above. After the process reaches steady-state, the skinningpipe pressure control may be activated.

FIG. 71 shows a plot representing an exemplary relationship between thereturn pressure and the skinning speed. The plot shows an exemplarylinear relationship between the return pressure and the skinning speed,which may be used for determining the return pressure set point based onthe desired skinning speed, as shown in equation (B-1) discussed above.

FIG. 72 shows a control diagram representing controls that may beimplemented by the skinning control system 410 to control the skinningprocess. The diagram shows a three-layer cascade control scheme 2190 forenabling delivery of defect-free or substantially defect-free skinnedarticles. The control scheme 2190 may include a first feed forwardcontrol 2195, a first feedback control 2201, a second feedback control2202, and a third feedback control 2203.

The first feed forward control 2195 may include a first feed forwardcontroller 2210. The first feed forward controller 2210 may determine achange or adjustment in the return pressure set point (e.g., the changein the target return pressure in the recirculation line 260) based on avariation in at least one of the viscosity or the flow rate of theflowable mixture. The variation in the viscosity and/or the flow ratemay be input to the first feed forward controller 2210 as disturbance(or the viscosity and/or the flow rate may be input into the first feedforward controller 2210 as disturbance). In some embodiments, theskinning control system 410 may receive measured viscosity and/or theflow rate from a viscometer and/or flow meter disposed in the mixturedelivery system 200, and the first feed forward controller 2210 maycalculate the variation in the viscosity and/or the flow rate. In someembodiments, the skinning control system 410 may receive a signaldirectly indicating a variation in the measured viscosity and/or flowrate.

Referring to FIG. 72, the first feedback control 2201 may include afirst feedback controller 2215. The first feedback controller 2215 maydetermine a pump speed (e.g., the speed of the pump 235) based on ameasured return pressure (e.g., a return pressure measured in therecirculation line 260). In some embodiments, the return pressure may bemeasured by a pressure sensor disposed within the recirculation line260. The first feedback control 2201 may include a saturation box 2225to prevent pump speed from going up too high. The measured returnpressure may be filtered by a filter 2225, which may be a digitalfilter, an analog filter, or a combination thereof. The filter 2225 maybe configured to remove noise from the measurement signal of the returnpressure. The filter 2225 may be optional. The measured return pressure(filtered or not filtered) may be compared with a return pressure setpoint (e.g., the desired return pressure) determined by a secondfeedback controller 2230, and the difference or error may be combinedwith the change in the return pressure set point determined by the firstfeed forward controller 2210, as indicated by a combination symbol 2235.The result of the combination may be fed into the first feedbackcontroller 2215 as an input.

Referring to FIG. 72, the second feedback control 2201 may include thesecond feedback controller 2230. The second feedback controller 2230 maydetermine a return pressure set point (e.g., the desired return pressurein the recirculation line 260) based on a measured skinning pipepressure (“unipipe pressure” in FIG. 72). The measured skinning pipepressure may be filtered by a filter 2240 to remove noise, which may bea digital filter, an analog filter, or a combination. The filter 2240may be optional. The skinning pipe pressure (filtered or not filtered)may be compared with a skinning pipe pressure set point (e.g., a desiredskinning pipe pressure) as indicated by the combination symbol 2245, andthe difference (or error) may be fed into the second feedback controller2230 to determine the return pressure set point. A saturation box 2250may be included to limit the return pressure set point outputted fromthe second feedback controller 2230.

Referring to FIG. 72, the third feedback control 2203 may include athird feedback controller 2255, which may determine a skinning pipepressure set point (e.g., a desired skinning pipe pressure set point)based on a result of monitoring presence of a defect in the skinnedarticle. In some embodiments, the third feedback controller 2255 maydetermine the skinning pipe pressure set point based on a type of defectdetected in the skinned articles. The at least one laser device 1555 maymonitor the presence of the defects, and if any, detect the defects inthe skinned articles. The skinning control system 410 or the laserdevice 1555 may determine (e.g., detect) the type of the defect, asindicated by box 2260. If the defect is a pit/pock type defect that isrelated to the density, the skinning control system 410 may check thedensity of the flowable mixture. If the defect is a fast flow orstarvation type of defect, which is related to the skinning pipepressure, this defect type information may be fed into the thirdfeedback controller 2255 along with quality specification, as indicatedby the combination symbol 2265. The quality specification may specifythat no fast flow and/or starvation type of defect should occur, or anacceptable range of defects that may occur. The measurements (e.g.,skinning pipe pressure, return pressure, defect type) shown in FIG. 72may be real-time or near real-time measurements. Although the type ofdefect may be a direct input to the third feedback controller 2255, thefirst and second feedback controllers 2215 and 2230 may also useinformation derived from the type of defect, as shown in the layeredfeedback control scheme 2190. Thus, the determinations made by the firstand second feedback controllers 2215 and 2230 may also be based on thetype of defect.

The skinning pipe control scheme relating to controls shown in FIG. 72is discussed below. As shown in FIG. 72, the skinning pipe pressure iscontrolled using a two-layer cascade control scheme. The inner loop(i.e., the first feedback control 2201) controls the return pressure inthe recirculation line 260 using the pump speed (e.g., of pump 235) andthe outer loop (i.e., the second feedback control 2202) controls theskinning pipe pressure by adjusting the return pressure set point. Themeasured return pressure and skinning pipe pressure signals are filteredto reduce noise so that the first and second feedback controllers 2215and 2230 do not respond to noise induced variations. One form of thefilters (e.g., filters 2225 and 2240) used to reduce noise in thepressure signals may be:

Pressure (k)=α×Pressure (k)+(1−α)×Pressure (k−1)  (C-4)

where ‘k’ is the sample time and ‘α’ is the filter parameter. This formof the filter as shown in equation (C-4) is a first order filter. Thesmaller the ‘α’ value, the more the signal will be filtered. This filtermay induce a time delay in the filtered signal. The ‘α’ value may bedesigned to achieve a balance between the amount of filtering and timedelay.

The filtered return pressure may be compared to the target returnpressure (e.g., return pressure set point) as determined by the secondfeedback controller 2230 and the difference (or error) is sent to thefirst feedback controller 2215, which may automatically adjust the pumpspeed to reduce the error between the measured and target returnpressures. The structure of the first feedback controller 2215 may be:

U _(FB) ^(I)(s)=G ₁ ⁻¹(s)F ₁(s)  (C-5)

where, U_(FB) ^(I)(s) is the output of the first feedback controller2215 in Laplace form, F₁(s) is the Laplace transform representation of alow pass filter and G₁ ⁻¹(s) is the inverse of the Laplace transformrepresentation of the process model between the pump speed and returnpressure. One form of the process model may be:

G ₁(s)=K ₁ e ^(−θ) ¹ ^(s)/(1+τ₁ s)  (C-6)

where, K₁, θ₁, τ₁ are the process gain, time delay, and the timeconstant respectively describing the relationship between the pump speedand the return pressure. The process model is a function of thecomposition of the flowable mixture and process design such as thelength of tubing from the pump 235 to the location of the returnpressure sensor, the type of tubing used, etc.

An example of the process model G₁(s) may be:

G ₁(s)=8e ^(−7s)/(1+15s)  (C-7)

The filtered skinning pipe pressure is compared to the target skinningpipe pressure and the difference (or error) is sent to the secondfeedback controller 2230. This controller automatically determines thedesired return pressure set point to reduce the error between themeasured skinning pipe pressure and the target skinning pipe pressure.The structure of the second feedback controller 2230 may be:

U _(FB) ^(II)(s)=C ₁ ⁻¹(s)G ₂ ⁻¹(s)F ₂(s)  (C-8)

where, U_(FB) ^(II)(s) is the output of the second feedback controller2230 in Laplace form, F₂(s) is the Laplace transform representation of alow pass filter, G₂ ⁻¹(s) is the inverse of the Laplace transformrepresentation of the process model across the manifold 305 defining thepressure drop dynamics between the return pressure and the skinning pipepressure and C₁ ⁻¹(s) is the inverse of the Laplace transform of theclosed loop representation of the inner control loop (i.e., the firstfeedback control 2201 loop).

One example of the structure of the process model G₂(s) may be of theform similar to the one shown in equation (C-6):

G ₂(s)=K ₂ e ^(−θ) ² ^(s)/(1+τ₂ s)  (C-9)

where, K₂, θ₂, τ₂ are the process gain, time delay, and the timeconstant respectively describing the relationship between the returnpressure and the skinning pipe pressure. This process model is also afunction of the composition of the flowable mixture, mixture deliveryprocess design from the location of the return pressure sensor to themanifold inlet (e.g., manifold inlet 1700) and the design of themanifold 305. The closed loop representation of the inner loop may be:

C ₁(s)=U _(FB) ^(I)(s)G ₁(s)/[1+U _(FB) ^(I)(s)G ₁(s)]  (C-10)

An example of the process model defining the relationship between thereturn pressure set point and skinning pipe pressure, given byC₁(s)×G₂(s) may be:

C ₁(s)×G ₂(s)=0.76e ^(−7.6s)/(1+22s)  (C-11)

A simple form of both feedback controllers given by, U_(FB) ^(I)(s) andU_(FB) ^(II)(s) may be:

U _(FB) ^(I)(s)=K _(P) ^(I) +K _(I) ^(I) /s  (C-12)

U _(FB) ^(II)(s)=K _(P) ^(II) +K _(I) ^(II) /s  (C-13)

where, K_(P) ^(I) and K_(I) ^(I) are the proportional and integral gainfor the first feedback controller 2215 and K_(P) ^(II) and K_(I) ^(II)are the proportional and integral gain of the second feedback controller2230.

Based on equations (C-7) and (C-11) it can be observed that the outerloop process (i.e., the second feedback control 2202 loop) is not muchslower than the inner loop process (i.e., the first feedback control2201 loop). Hence, K_(P) ^(I) and K_(I) ^(I) are so designed such thatthe inner loop control (i.e., first feedback control 2201) is at least 5times faster than the outer control loop (i.e., the second feedbackcontrol 2202), for example, 10 times faster. Example values of thecontroller parameters may be:

K _(P) ^(I)=0.1;K _(I) ^(I)=0.6;K _(P) ^(II)=0.8;K _(I)^(II)=2.6  (C-14)

FIG. 73 shows a control diagram representing controls that may beimplemented by the skinning control system 410 to control the skinningprocess. The control scheme 2300 may include a second feed forwardcontrol 2305, which may include a second feed forward controller 2310.The second feed forward controller 2310 may determine a change oradjustment in the pump speed (e.g., the speed of the pump 235) and/orthe delivery valve position (e.g., the opening of the delivery valve245) based on a variation in at least one of the viscosity or flow rateof the flowable mixture, which may be input into the second feed forwardcontroller 2310 as disturbance.

The control scheme 2300 may include a fourth feedback control 2314 and afifth feedback control 2315. The fourth feedback control may include afilter 2320 configured to remove noise in the measured skinning pipepressure, and a fourth feedback controller 2324 configured to determinethe pump speed and/or the delivery valve position based on the measuredskinning pipe pressure.

The fifth feedback control 2315 may include a fifth feedback controller2325, which may determine a skinning pipe pressure set point based on aresult of monitoring presence of a defect in the skinned articles. Insome embodiments, monitoring the presence of the defect may includedetecting a type of the defect, when the defect is present. The fifthfeedback controller 2325 may determine the skinning pipe pressure setpoint based on the type of the defect in the skinned articles. Theoutput of the fourth feedback controller 2324 may be the pump speedand/or the delivery valve position, which may be combined with theadjustment in the pump speed and/or the delivery valve position outputfrom the second feed forward controller 2310, as indicated by acombination symbol 2330. The combination of the output from the secondfeed forward controller 2310 and the fourth feedback controller 2324 isthe total pump speed and/or delivery valve position, which are then usedby the mixture control system 405 to adjust the pump speed and/or thedelivery valve position. The outputs combination may be limited by asaturation box 2335 included in the fourth feedback control 2314.

Referring to FIG. 73, the filtered skinning pipe pressure (or notfiltered, since the filter 2320 may not be included) may be comparedwith a skinning pipe pressure set point output from the fifth feedbackcontroller 2325, as indicated by the combination symbol 2340. Thedifference (or error) may be fed into the fourth feedback controller2324 as an input to determine the pump speed and/or the delivery valveposition. The fifth feedback control 2315 may receive the qualitymeasurement, e.g., a result of monitoring that may include informationregarding the presence of the defects, from the at least one laserdevice 1555. The laser device 1555 may continuously monitoring presenceof a defect on the skin of a skinned article. When the defect is presenton the skin, the laser device 1555 may detect the defect. The skinningcontrol system 410 and/or the laser device 1555 may determine the typeof the defect (e.g., a fast flow type, a starvation type, a pit type, apock type, a ring type, etc.), as indicated by the box 2345. If the typeof the defect is pits/pocks, the skinning control system 410 maycommunicate with the mixture control system 405 to check the density ofthe flowable mixture. If the type of the defect is fast flow and/orstarvation, this defect type information may be fed into the fifthfeedback controller 2325 along with the quality specification, asindicated by the combination symbol 2350.

The skinning pipe control scheme relating to controls shown in FIG. 73is discussed below. In this embodiment, the skinning pipe pressure maybe directly controlled using the pump speed and/or the delivery valve(e.g., delivery valve position). The filtered skinning pipe pressure maybe compared to the target skinning pipe pressure (e.g., the skinningpipe pressure set point) and the difference (or error) is sent to thefourth feedback controller 2324. This controller automatically adjuststhe pump speed and/or the delivery valve position to reduce the errorbetween the measured skinning pipe pressure and the target skinning pipepressure.

The structure of the fourth feedback controller 2324 may be:

U _(FB) ^(IV)(s)=G ₄ ⁻¹(s)F ₄(s)  (C-15)

where, U_(FB) ^(IV)(s) is the output of the fourth feedback controller2324 in Laplace form, F₄(s) is the Laplace transform representation of alow pass filter and G₄ ⁻¹(s) is the inverse of the Laplace transformrepresentation of the process model between the pump speed or thedelivery valve position and skinning pipe pressure, depending on whichone of the pump speed or the delivery valve position is selected for thecontrol.

A single feedback controller may be used for controlling the skinningpipe pressure, as described in this embodiment instead of the cascadecontrol described in FIG. 72. The cascade control scheme shown in FIG.72 may provide some ease of implementation benefits. If for some reason,the skinning process is stopped, then only the outer loop (i.e., thesecond feedback control 2202 loop) need to be turned off while the innerloop (i.e., the first feedback control 2201 loop) continues to executeto control the flowable mixture return pressure using the pump speed. Inthe case of the single feedback controller option, as shown in FIG. 73,whenever the skinning process is stopped, not only does the feedbacksignal may need to be switched (from skinning pipe pressure to returnpressure), the controller parameters may also need to be changed.Another advantage of the cascade control architecture shown in FIG. 72is the ability to tune the inner loop (i.e., the second feedback control2202 loop) relatively fast so that the inner loop will be able to rejectany disturbances caused in the flowable mixture delivery line as thereturn pressure will detect this sooner than the skinning pipe pressure.

FIG. 74 shows a control diagram representing controls that may beimplemented by the skinning control system 410 to control the skinningprocess. The control scheme 2360 shown in FIG. 74 may be similar to thecontrol scheme shown in FIG. 72, except for the feed forward control.The feed forward control in the control scheme 2360 may determine anadjustment or change in the flow rate set point (e.g., target flowrate), rather than the in the return pressure set point, as shown in thecontrol scheme of FIG. 72.

Referring to FIG. 74, the control scheme 2360 may include a third feedforward control 2365, which may include a third feed forward controller2370 configured to determine an adjustment or change in the flow rateset point. A variation in at least one of the viscosity or the flow ratemay be input into the third feed forward controller 2370 as disturbance.The control scheme 2360 may include a sixth feedback control 2366, aseventh feedback control 2367, and an eighth feedback control 2368.

The sixth feedback control 2366 may include a sixth feedback controller2376, the seventh feedback control 2367 may include a seventh feedbackcontroller 2377, and the eighth feedback control 2368 may include aneighth feedback controller 2378. The sixth feedback controller 2376 maybe configured to determine a pump speed based on a measured flow rate inthe delivery line 240. The flow rate may be measured by a flow meterdisposed downstream of the pump 235. The measured flow rate may befiltered by a filter 2380 to remove noise in the flow rate measurement.The filtered (or not filtered since the filter 2380 may not be includedin some embodiments) may be compared with a flow rate set point outputfrom the seventh feedback controller 2377, as indicated by thecombination symbol 2385. The difference (or error) is fed into the sixthfeedback controller 2376 along with the adjustment in the flow rate setpoint output from the third feed forward controller 2370. The sixthfeedback controller 2376 may determine a pump speed. The output pumpspeed may be limited by a saturation box 2390, which is then be used bythe mixture control system 405 to adjust the pump 235.

Referring to FIG. 74, the seventh feedback controller 2377 may determinethe flow rate set point based on the measured skinning pipe pressure.The measured skinning pipe pressure may be filtered by a filter 2395 toremove noise. The filtered skinning pipe pressure (or not filtered sincethe filter 2395 may be optional) may be compared with a skinning pipepressure set point output from the eighth feedback controller 2378, asindicated by a combination symbol 2400. The difference (or error) may beinput into the seventh feedback controller 2377 to determine the flowrate set point. The flow rate set point output from the seventh feedbackcontroller 2377 may be limited by a saturation box 2405.

The eighth feedback controller 2378 may determine the skinning pipepressure set point based on a result of monitoring presence of a defectin the skinned article. For example, the eighth feedback controller 2378may determine the skinning pipe pressure set point based on a type ofthe defect in the skinned articles. The skinning control system 410 mayreceive signals from the at least one laser device 1555, which mayinclude information regarding the presence of the defects (e.g., whetherdefects are detected) in the skinned articles, and may determine, basedon the received signals, the type of the defect in the skinned article,as indicated by the box 2410. Alternatively, the laser device 1555 maydetect the type of the defect. If the type of the defect is pit/pock,the skinning control system 410 may communicate with the mixture controlsystem 405 to check the density of the flowable mixture. If the type ofthe defect is fast flow and/or starvation, this type of defectinformation may be fed into the eighth feedback controller 2378 alongwith the qualify specification, as indicated by a combination symbol2415.

Models for the controllers shown in FIG. 74 may be similarly designed,as those described above in equations (C-4) to (C-14), except that thespecific design values shown in (C-7), (C-11), and (C-14) may bedifferent.

Referring to the controls shown in FIGS. 72-74, the skinning pipepressure control parameters (e.g., parameters used by at least one ofthe first feedback controller 2215, second feedback controller 2230,fourth feedback controller 2324, sixth feedback controller 2376, orseventh feedback controller 2377) need to be adjusted as a function ofthe skinning speed. For slower skinning speeds the pressure dropdynamics across the manifold 305 is much slower than for higher skinningspeeds. So if the control parameters that were determined for higherskinning speeds are used for slower skinning speeds, the controllerperformance would be very aggressive which might not be a desirable froma process standpoint. Hence the control parameters need to be optimizedas a function of the skinning speed.

The control schemes shown in FIGS. 72-74 enables the control system 400to adjust the process set points (e.g., at least one of the returnpressure set point, the delivery pressure set point, the skinning pipepressure set point, or the flow rate set point) automatically based onthe monitoring of the presence of the defect in the final skinnedarticles (e.g., based on the type of defect detected on the finalskinned articles). By using the feed forward controls 2195, 2305, and2365, the control system 400 may proactively compensate for variationsin the properties of the flowable mixture, such as the flow rate andviscosity. The feedback, such as, the quality measurement (e.g.,measured defect), the skinning pipe pressure measurement, the returnpressure measurement, or the flow rate measurement, may be real-time ornear real-time feedback. The inputs (e.g., disturbance) to the feedforward controllers, such as the viscosity and/or flow rate, or theirvariations, may also be real-time or near real-time inputs.

FIG. 75 shows a sample plot showing the performance of the skinning pipepressure control scheme 2190 shown in FIG. 72. The plot shows the returnpressure (A), the skinning pipe pressure (B), and the pump speed versustime. The control scheme 2190 may be configured to maintain the skinningpipe pressure within reasonable tolerance of the desired target value of3 psi. The standard deviation of the skinning pipe pressure may be lessthan 0.2 psi for the whole run of about 85 articles. When smallerdimension (e.g., diameter) articles go through the process, the controlscheme 2190 may automatically adjust the return pressure to compensatefor the smaller dimension (e.g., diameter) articles and continue tomaintain the skinning pipe pressure within tolerance of the targetvalue.

Referring to the controls shown in FIGS. 72-74, the feed forwardcontrollers 2210, 2310, and 2370 may be different, but their designs mayshare the same design philosophy. An example design of the first feedforward controller 2210 shown in FIG. 72 is discussed below forillustrative purposes. The second and third feed forward controllers2310 and 2370 may be similarly designed. The structure of the first feedforward controller 2310 shown in FIG. 72 may be shown in below equation(C-16):

U _(FF)(s)=[G _(P) ⁻¹(s)]Q _(D)(s)  (C-16)

where, U_(FF)(s) is the Laplace transform of the output of the firstfeed-forward controller 2210, Q_(D)(s) is the Laplace transform of thefeed-forward model predicted impact of the viscosity on skinning pipepressure and G_(P) ⁻¹(s) is the inverse of the Laplace transform of theprocess model between return pressure set point and the skinning pipepressure.

The traditional approach of feed-forward control scheme is to obtain themodel between the disturbance (e.g., the viscosity) and the processoutput (e.g., the skinning pipe pressure) so that the model can be usedto predict the output drifts based on disturbance changes. The secondstep is to determine the change in the control action needed to offsetthe predicted process output drift using the process model between thecontrol actuator (e.g., the return pressure set point) and the processoutput.

FIG. 76 shows an exemplary relation between viscosity and returnpressure set point to maintain the same skinning pipe pressure. Thisrelation is useful in designing the first feed forward controller 2210shown in FIG. 72. This may be another way of implementing feed-forwardcontrol. In this case, a model between the disturbance (e.g., theviscosity) and the control actuator (e.g., the return pressure setpoint) may be obtained and the inverse of this model may be used as thefirst feed-forward controller 2210. An exemplary form of this controllermay be a proportional only controller. Using the relation shown in FIG.76, the feed forward controller 2210 gain may be obtained as shown inequation (C-17):

Kc=ΔBRP/Δviscosity=0.0009  (C-17)

where ΔBRP is the change in return pressure set point and Δviscosity isthe change in the viscosity of the flowable mixture. The governingequation of the first feed forward controller 2210 may be shown inequation (C-18):

U _(FF)(k+τ)=Kc(ΔViscosity(k))  (C-18)

where, k is the sample time, U_(FF)(.) is the output of the firstfeed-forward controller 2210, τ is the transport delay defined as thetime the first feed-forward controller 2210 takes for the flowablemixture to travel from the location of the viscosity measurement to thelocation of the skinning pipe pressure measurement, and ΔViscosity(k) isthe change in viscosity defined as shown in equation (C-19):

ΔViscosity(k)=Viscosity(k)−Viscosity(k−1)  (C-19)

The output of the first feed-forward controller 2210 is the change inthe return pressure set point needed to compensate for any incomingviscosity variations. This output is combined with the output of thesecond feedback controller 2230 shown in FIG. 72 to obtain the finalcontroller output defined as shown in equation (C-20):

U(s)=U _(FB) ^(II)(s)−U _(FF)(s)  (C-20)

The second feed forward controller 2310 and third feed forwardcontroller 2370 may be designed similarly using the principles describedabove for the design of the first feed forward controller 2210. Similarto the model shown in FIG. 76 for the first feed forward controller2210, a model between viscosity and pump speed may be obtained for thesecond feed forward controller 2310 to maintain the same skinning pipepressure and a model between the viscosity and flow rate may be obtainedfor the third feed forward controller 2370.

Referring to FIGS. 72-74, although return pressure and return pressureset point are used in the controls, they may be replaced by deliverypressure (e.g., the pressure in the delivery line 240) and deliverypressure set point.

FIG. 77 shows an exemplary control scheme 2450 for controlling theskinning pipe pressure. Variations in the unskinned article dimensions(e.g., diameter, radius, circumference, axial length, and/or outerperipheral length) may affect the skinning pipe pressure. Forillustrative purposes, the variations in the unskinned articledimensions (e.g., diameters) refer to the dimension (e.g., diameter)variations in different articles, although the variation in thedimension (e.g., diameter) within a single article may also be used inthe control of the skinning pipe pressure. FIG. 79 shows a sample plotshowing the impact of incoming article dimension (e.g., diameter)variations on the skinning pipe pressure (or unipipe pressure). The plotshows that the greater the magnitude of variation, the greater theimpact on the skinning pipe pressure in terms of sustained oscillations.The existence of the sustained oscillations results in the loss of theprocess window for the skinning process.

Referring back to FIG. 77, to compensate for the pressure change in theskinning pipe that may be caused by the variations in the unskinnedarticle dimensions (e.g., diameter, radius, circumference, axial length,and/or outer peripheral length), the control scheme 2450 may include afeed forward control 2455 that includes a feed forward controller 2460configured to estimate (or predict, calculate, determine) an adjustmentor change to a skinning speed based on the variation in the measuredincoming article dimensions (e.g., diameters). The variation in theincoming article dimensions (e.g., diameters) may be fed into the feedforward controller 2460 as disturbance.

The control scheme 2450 may include a feedback control 2465 thatincludes a feedback controller 2470. The feedback controller 2470 maydetermine the skinning speed based on the measured skinning pipepressure. The measured skinning pipe pressure may be compared with askinning pipe pressure set point, as indicated by a combination symbol2475. The feedback control 2465 may include a filter to remove noisefrom the measured skinning pipe pressure, similar to the filter 2240shown in FIG. 72. The skinning speed determined by the feedbackcontroller 2470 may be combined with the adjustment to the skinningspeed determined by the feed forward controller 2460, as indicated bythe combination symbol 2480. The result of the combination is then fedinto a saturation box 2485, which limits the skinning speed. Theskinning control system 410 may use the skinning speed thus determinedto control the skinning system 300. For example, the skinning controlsystem 410 may send a signal to at least one of the lower servo motor1535 or the upper servo motor 1545 shown in FIG. 26 to control the speedof the skinning. As shown in FIGS. 52 and 53, the incoming unskinnedarticle dimension (e.g., diameter) may be measured by the laser devices1560, which may transmit the dimension (e.g., diameter) signals or datato the skinning control system 410. The measurement of the incomingarticle dimensions (e.g., diameters) may be real-time or near real-timemeasurement. By controlling the skinning speed, the skinning pipepressure may be controlled.

The control scheme 2450 shown in FIG. 77 uses the skinning speed as thecontrol parameter, which is adjusted by the skinning control system 410,such that a desired skinning pipe pressure set point is maintained atthe skinning pipe 310. Alternatively or additionally, the pressurerelief system position may be used as the control parameter, as shown inFIG. 78. That is, the pressure relief system 1755 shown in FIGS. 38-41,43, and 44 may be adjusted based on the output from the feed forwardcontroller, as shown in FIG. 78, to control the skinning pipe pressuresuch that it is within an acceptable range of the skinning pipe pressureset point.

The control scheme 2490 shown in FIG. 78 may include a feed forwardcontrol 2495, which may include a feed forward controller 2500. The feedforward controller 2500 may determine an adjustment or change to thepressure relief system position (e.g., how much the pressure reliefsystem 1755 should move the lower ring 1720, which in turn affects theskinning pipe pressure) based on the variation in the measured incomingunskinned article dimension (e.g., diameter).

The control scheme 2490 may include a feedback control 2505, which mayinclude a feedback controller 2510 that may determine a pressure reliefsystem position based on the measured skinning pipe pressure. Themeasured skinning pipe pressure may be compared with the skinning pipepressure set point, as indicated by the combination symbol 2515. Thedifference (or error) may be fed into the feedback controller 2510. Thepressure relief system position output from the feedback controller 2510may be combined with the adjustment to the pressure relief systemposition determined by the feed forward controller 2500, as indicated bythe combination symbol 2520. The combined result may be limited by asaturation box 2525. The pressure relief system position output from thesaturation box 2525 may be used by the skinning control system 410 tocontrol the pressure relief system 1755. For example, the skinningcontrol system 410 may send a signal to the pressure relief system 1755to adjust the lower ring 1720, such that the skinning pipe pressure isadjusted. The measured skinning pipe pressure may be filtered by afilter (e.g., a digital or analog filter) to remove noise.

Referring to FIGS. 77 and 78, the feedback controller design will bediscussed. The feedback controllers 2470 and 2510 may be different, butthe design philosophy may be the same or similar in the sense that theskinning pipe pressure is monitored and compared to a target skinningpipe pressure (e.g., the skinning pipe pressure set point) and ancontrol parameter (e.g., the skinning speed or the pressure reliefsystem position) is adjusted to compensate for any pressure change dueto incoming unskinned article dimension (e.g., diameter) variation. Thecontrol parameter for the control scheme of FIG. 77 is the skinningspeed while the control parameter for the control scheme of FIG. 78 isthe position of the pressure relief system 1755 (or the pressure reliefsystem position). The process dynamics between the skinning speed andskinning pipe pressure may be different from the process dynamicsbetween the pressure relief system position and skinning pipe pressure.The measured pressure signal may be filtered to reduce noise so that thedesigned controller does not respond to noise induced variations. Thecontrol schemes 2450 and 2490 shown in FIGS. 77 and 78 may beincorporated into the control schemes shown in FIGS. 72-74, in additionto or instead of the skinning pipe pressure control schemes disclosed inFIGS. 72-74.

One exemplary form of filter design is shown in equation (C-4) discussedabove. The filtered (or not filtered) skinning pipe pressure is comparedto the target skinning pipe pressure (e.g., skinning pipe pressure setpoint) and the difference (or error) may be sent to the feedbackcontroller 2470 or 2510, which automatically adjusts the controlparameter (either the skinning speed or the pressure relief systemposition) to compensate for the pressure change due to the variation inthe incoming article dimension (e.g., diameter). The controller may onlyreact if the error is greater than a certain value (deadband). If not,the controller output may not change.

The structure of the feedback controller 2470, when the error betweenthe measured skinning pipe pressure and the target skinning pipepressure is greater than the deadband, may be:

U _(FB) ^(I)(s)=G ₁ ⁻¹(s)F ₁(s)  (C-21)

where, U_(FB) ^(I)(s) is the output of the feedback controller 2470 inLaplace form, F₁(s) is the Laplace transform representation of a lowpass filter and G₁ ⁻¹(s) is the inverse of the Laplace transformrepresentation of the process model between the skinning pipe pressureand skinning speed. The process dynamics between the skinning speed andthe skinning pipe pressure may be reverse acting as an increase in theskinning speed results in a decrease in the skinning pipe pressure.Hence, it may be desirable to design the controller to be direct acting.That means that if an increase in skinning pipe pressure is detected,the skinning speed should be increased to reduce the skinning pipepressure.

One form of the process model may be:

G ₁(s)=−K ₁ e ^(−θ) ¹ ^(s) Y/(1+τ₁ s)  (C-22)

where, K₁, θ₁, τ₁ are the process gain, time delay, and the timeconstant respectively describing the relationship between the skinningspeed and skinning pipe pressure. Note that the process gain K₁ isnegative describing the reverse acting nature of the process.

The structure of the feedback controller 2510, when the error betweenthe measured skinning pipe pressure and the target skinning pipepressure is greater than the deadband, may be:

U _(FB) ^(II)(s)=G ₂ ⁻¹(s)F ₂(s)  (C-23)

where, U_(FB) ^(II)(s) is the output of the feedback controller 2510 inLaplace form, F₂(s) is the Laplace transform representation of a lowpass filter and G₂ ⁻¹(s) is the inverse of the Laplace transformrepresentation of the process model between the skinning pipe pressureand pressure relief system position. The process dynamics between thepressure relief system position and the skinning pipe pressure is directacting, as an increase in the position of the pressure relief systemresults in an increase in the skinning pipe pressure. Hence, it may bedesirable to design the controller to be reverse acting. That means thatif an increase in skinning pipe pressure is detected, the pressurerelief system position should be decreased to reduce the skinning pipepressure.

One form of the process model may be:

G ₂(s)=K ₂ e ^(−θ) ² ^(s)/(1+τ₂ s)  (C-24)

where, K₂, θ₂, τ₂ are the process gain, time delay, and the timeconstant respectively describing the relationship between the pressurerelief system position and skinning pipe pressure.

One exemplary form of the feedback controller may be a proportional onlycontroller:

U _(FB) ^(I)(s)=−1/K ₁  (C-25)

U _(FB) ^(II)(s)=1/K ₂  (C-26)

The final form of the controller in time domain may be:

For the feedback controller 2470 shown in FIG. 77 that uses skinningspeed as the control parameter:

U _(FB) ^(I)(k)=U _(FB) ^(I)(k−1);e(k)≦deadband  (C-27)

U _(FB) ^(I)(k)=U _(FB) ^(I)(k−1)−[e(k)−e(k−1)]/K ₁;e(k)>deadband  (C-28)

For the feedback controller 2510 shown in FIG. 78 that uses pressurerelief system position as the control parameter:

U _(FB) ^(II)(k)=U _(FB) ^(II)(k−1);e(k)≦deadband  (C-29)

U _(FB) ^(II)(k)=U _(FB) ^(II)(k−1)+[e(k)−e(k−1)]/K ₂;e(k)>deadband  (C-30)

where e(k) is defined as:

e(k)=Skinning Pipe Pressure Set Point−Skinning Pipe Pressure (k)  (C-31)

Example nominal values of the deadband may range from 0.2 psi to 0.8psi.

The controller design for the feed forward controllers 2460 and 2500shown in FIGS. 77 and 78 is discussed below. The feed-forward controllerdepends on the predicted impact of the incoming article dimension (e.g.,diameter) variation on the skinning pipe pressure. If the predictedimpact on the skinning pipe pressure is within a certain threshold, thefeed-forward controller output may be held substantially constant andnot changed. This can also be stated as follows: if the incoming articledimension (e.g., diameter) variation is within a certain range, then thefeed-forward controller output may be held substantially constant andnot changed. The feed-forward controller may become active only when theincoming article dimension (e.g., diameter) variation is outside thelimits.

The structure of the feed forward controller 2460 shown in FIG. 77 maybe:

U _(FF) ^(I)(s)=[G ₁ ⁻¹(s)]Q _(D)(s)  (C-32)

where, (s) is the Laplace transform of the output of the feed forwardcontroller 2460, (s) is the Laplace transform of the feed-forward modelpredicted impact of the incoming article dimension (e.g., diameter)variation on the skinning pipe pressure and G₁ ⁻¹(s) is the inverse ofthe Laplace transform of the process model between skinning speed andthe skinning pipe pressure as shown in equation (C-22). Similarly, thestructure of the feed forward controller 2500 as shown in FIG. 78 maybe:

U _(FF) ^(II)(s)=[G ₂ ⁻¹(S)]Q _(D)(s)  (C-33)

One example of a feed forward control structure is described below. FIG.80 shows a sample plot showing the impact of incoming article dimension(e.g., diameter) variations on the skinning pipe pressure in aregression form. The plot shows the skinning pipe pressure change orvariation versus the incoming article dimension (e.g., diameter) changeor variation. As shown in FIG. 80, there is a linear relationshipbetween the change in the skinning pipe pressure and the variation inthe incoming article dimensions (e.g., diameters). Based on FIG. 80, theimpact of the incoming article dimension (e.g., diameter) variation onthe unipipe pressure can be simplified as:

Q _(D)(s)=4.2×e _(D)(k)  (C-34)

where, e _(D)(k) is defined as:

e _(D)(k)=nominal article diameter−incoming article diameter (k)  (C-35)

Combining equations (C-25), (C-26), and (C-34), for the feed forwardcontroller 2460 shown in FIG. 77, where skinning speed is a controlparameter, the model is:

U _(FF) ^(I)(k+τ)=U _(FF) ^(I)(k−1);e _(D)(k)≦diameter deadband  (C-36)

U _(FF) ^(I)(k+τ)=−[4.2×e _(D)(k)]/K ₁ ;e _(D)(k)>diameterdeadband  (C-37)

For the feed forward controller 2500 shown in FIG. 78, where thepressure relief system position is used as a control parameter, themodel is:

U _(FF) ^(II)(k+τ)=U _(FF) ^(II)(k−1);e _(D)(k)≦diameterdeadband  (C-38)

U _(FF) ^(II)(k+τ)=[4.2×e _(D)(k)]/K ₂ ;e _(D)(k)>diameterdeadband  (C-39)

where, τ is defined as the time it takes for the incoming article toreach the location in the skinning process when the impact on theskinning pipe pressure will be seen. Example nominal values of thediameter deadband could range from +/−0.05 mm to +/−0.1 mm.

FIG. 81 is a flowchart illustrating an exemplary method 2550 forcontrolling the skinning pipe pressure. The method 2550 may be performedby the skinning control system 410. The method 2550 may include startingthe skinning process, activating the start-up control, and activating afirst (e.g., primary) skinning pipe pressure control (block 2555). Theprimary skinning pipe pressure control refers to the skinning pipepressure controls shown in FIGS. 72-74. For illustrative purposes, belowdiscussion uses the skinning pipe pressure control of FIG. 72 as theprimary skinning pipe pressure control.

The method 2550 may include determining whether an incoming articledimension (e.g., diameter) is outside limits (block 2560). When theskinning control system 410 determines that the incoming articledimension (e.g., diameter) is not outside the limits (No, block 2560),the process may repeat the determining block 2560 when the next incomingarticle dimension (e.g., diameter) is measured. When the skinningcontrol system 410 determines that the incoming article dimension (e.g.,diameter) is outside the limits (Yes, block 2560), the skinning controlsystem 410 may perform at least one of the operations listed in block2565. For example, the skinning control system 410 may switch off theprimary skinning pipe pressure control, and may hold the last value ofthe return pressure set point input to the first feedback control 2201.

The skinning control system 410 may activate a second (e.g., secondary)skinning pipe pressure control, which may be one of the two skinningpipe pressure controls disclosed in FIGS. 77 and 78. In block 2570, theskinning control system 410 may determine whether the dimensions (e.g.,diameters)s of the next three consecutive articles are within thelimits. When they are not within the limits (No, block 2570), theprocess may repeat the determining block 2570 based on the next threeconsecutive articles. When they are within the limits (Yes, block 2570),the skinning control system 410 may perform at least one of theoperations listed in block 2575. For example, the skinning controlsystem 410 may revert back to the primary skinning pipe pressurecontrol, and may slowly move the secondary skinning pipe pressurecontrol parameters (e.g., the skinning speed or the pressure reliefsystem position) to their respective baseline conditions (e.g., theskinning speed is revert back to its normal speed, and the pressurerelief system position is moved to a neutral position which neitherincreases nor reduces the skinning pipe pressure). In block 2570, thenumber three may be any other suitable number, e.g., one, two, four,five, etc. After block 2575, the process may repeat starting with block2560.

Force Triggered Motion Control

The force sensors 1645 and 1960 shown in FIG. 66 may be used to controlthe motion of the upper carriage 1540 and the lower carriage 1525 duringthe skinning process. Control of the motion of the upper carriage 1540and the lower carriage 1525 based on the force measured by the forcesensors 1645 and 1960 may be referred to as force triggered motioncontrol.

FIG. 82 shows measured forces experienced by the upper carriage 1540 andthe lower carriage 1525 while the skinning system 300 skins articleswith height variation of 1.03 mm in which force triggered motion controlis not activated. The upper and lower axes positions are also plotted inFIG. 82. Diagrams are included which show the articles in various stagesof the skinning process. As shown, the hand-off forces varied from aslittle as about 100 pounds for one article, to as much as 450 pounds foranother article. A force of 450 pounds would cause excessive wear of thecarriages and ball screw actuators for those carriages if this level offorce would be allowed to exist at production rates for an extendedperiod of time. Furthermore, each time a large force occurs at hand-off,a “ring” defect feature is created on the article being skinned, asshown in FIG. 84(A). This defect is the result of excessive squeezedisplacement of the rubber member of the vacuum chuck and abrupt motionof the article being skinned with respect to the skinning pipe 310.

Referring to FIG. 82, an example of the force triggered motion controlmay be described as follows. The upper axis, which includes the uppercarriage 1540 and the vacuum system 320, may holds (or grip) and pullone or more (e.g., two shown in FIG. 82) articles through the skinningpipe 310. In some embodiments, the vacuum system 320 may hold and pulltwo or more articles simultaneously. An unskinned article may be loadedonto the lower axis (which includes the lower carriage 1525 and thearticle feeding mechanism 315). The lower carriage 1525 may rapidlytraverse such that the top of the unskinned article nearly touches thebottom of the lowest article held and pulled by the vacuum system 320.The lower axis may slow down and move at a speed that is slightlygreater than that of the upper axis.

When a predetermined force value (e.g., 50 pounds) is detected, thecontrol system 400 (e.g., the skinning control system 410) may adjustthe speed of the lower axis to match the speed of the upper axis. Theupper axis and the lower axis may move together at the same speed for apredetermined period of time (e.g., 1 second), which may depend on theskinning speed. The upper axis may then move upward at a rapid speed toa position where the skinned article can be unloaded. After the skinningarticle is unloaded, the upper axis may then rapidly move to a positionsuch that the vacuum chuck is slightly higher than the top of the toparticle that is being pushed through the skinning pipe 310 by the loweraxis.

The upper axis may stop and wait until a force measured by the forcesensors 1645 reaches or exceeds the predetermined force value (e.g., 50pounds). After the force reaches or exceeds the predetermined forcevalue, the skinning control system 410 may then adjust the speed of theupper axis to be the same as the speed of the lower axis. The upper axisand lower axis may move at the same speed for the predetermined periodof time (e.g., 1 second). The lower axis may then move downward a rapidspeed to a position where a new unskinned article may be loaded onto theplaten 1515. This cycle may repeat until the skinning process isterminated or paused.

FIG. 83 shows a plot of measured forces experienced while skinningarticles with height variation of 1.03 mm in which force triggeredmotion control was used. The upper and lower axes positions are alsoplotted. A force value of 50 pounds was used as the trigger. As shown,even when articles with large height variations are put through theprocess, the peak forces remain less than approximately 190 pounds andthey remain substantially consistent. No “ring” part defects wereexperienced during this run of parts, as shown in FIG. 84(B).

FIG. 85 is a flowchart illustrating an exemplary method 2600 ofcontrolling the system 100. The method 2600 may be performed by thecontrol system 400. The method 2600 may include pushing, e.g., by thearticle feeding mechanism 315, an article into an inner space of askinning pipe (block 2605). The method 2600 may include applying aflowable mixture to the article using the skinning pipe as the articlemoves axially along the inner space of the skinning pipe (block 2610).The method 2600 may include measuring a variation in at least one of aflow rate, a viscosity, or dimensions (e.g., diameters)s of incomingunskinned articles (block 2615). The method 2600 may includedetermining, using a feed forward controller, an adjustment to at leastone of a delivery pressure set point, a return pressure set point, aspeed of a pump, a delivery valve position, a flow rate set point, askinning speed, or a pressure relief system position, based on themeasured variation (block 2620).

The method 2600 may include monitoring presence of a defect in a skinnedarticle coated with the flowable mixture (block 2625). Monitoring thepresence may include detecting a defect and determining a type of thedefect. The method 2600 may include determining, using a feedbackcontroller, at least one of a pipe pressure set point, the deliverypressure set point, the return pressure set point, the speed of thepump, the delivery valve position, or the flow rate set point, based ona result of monitoring the presence of the defect (e.g., based on thedetected type of defect) (block 2635). The method 2600 may includetransmitting a control signal to at least one of a mixture deliverysystem or a skinning system based on an output from at least one of thefeed forward controller or the feedback controller (block 2640).

FIG. 86 is a flowchart illustrating an exemplary method 2700 ofcontrolling the mixture delivery system 200. The method 2700 may beperformed by the mixture control system 405. The method 2700 may includecontinuously mixing a dry material and a fluid to produce a highlyviscous mixture having a viscosity of greater than one millioncentipoises (block 2705). The method 2700 may include storing the highlyviscous mixture in a storage device (block 2710). The method 2700 mayinclude continuously pumping the highly viscous mixture from the storagedevice to a delivery line leading to a skinning system at a flow rateranging from 50 pound/hour to 300 pound/hour (block 2715). The method2700 may include continuously recirculating a portion of the highlyviscous mixture from the delivery line back to the storage device (block2720).

FIG. 87 is a flowchart illustrating an exemplary method 2800 ofcontrolling the fluid dispensing system 215. The method 2800 may beperformed by the mixture control system 405. The method 2800 may includepumping a fluid from a storage tank to recirculate within arecirculation loop, the recirculation loop returning a portion of thefluid pumped out of the storage tank back to the storage tank (block2805). The method 2800 may include measuring a pressure in therecirculation loop (block 2810). The method 2800 may include adjusting aposition of a proportional flow control valve disposed within therecirculation loop based on at least one of a speed of the pump or themeasured pressure to maintain a substantially constant pressure withinthe recirculation loop while the fluid is delivered to the plurality ofdistribution branches (block 2815).

FIG. 88 is a flowchart illustrating an exemplary method 2900 ofcontrolling the system 100. The method 2900 may be performed by thecontrol system 400. The method 2900 may include circulating a flowablemixture within a recirculation line (block 2905). The method 2900 mayinclude measuring at least one of a return pressure or a deliverypressure associated with the flowable mixture (block 2910). The method2900 may include determining whether the at least one of the returnpressure or the delivery pressure is within a predetermined rangecompared to at least one of a return pressure set point or a deliverypressure set point (block 2915). The method 2900 may include, based onthe determination that the at least one of the return pressure or thedelivery pressure is within the predetermined range, directing theflowable mixture to a delivery line leading to a skinning system thatapplies the flowable mixture to an article (block 2920). The method 2900may include determining whether a skinning pipe pressure reaches astart-up pressure (block 2925). The method 2900 may include, based on adetermination that the skinning pipe pressure reaches the start-uppressure, starting the skinning process using the skinning system toapply the flowable mixture to the article (block 2930).

FIG. 89 is a flowchart illustrating an exemplary method 3000 ofcontrolling the skinning system 300. The method 3000 may be performed bythe skinning control system 410. The method 3000 may include determiningwhether a target skinning speed is greater than a predetermined skinningspeed (block 3005). When the target skinning speed is greater than apredetermined skinning speed (Yes, block 3005), the method 3000 mayinclude deactivating the pressure boost system to increase the space(e.g., space 1810) adjacent the skinning pipe available for the flowablemixture to flow (block 3010). The method 3000 may also include startingthe skinning process after deactivating the pressure boost system (block3015). The method 3000 may also include activating the pressure boostsystem to reduce the space adjacent the skinning pipe available for theflowable mixture to flow after the pipe pressure decreases to thepredetermined threshold pipe pressure (block 3020).

Referring to FIG. 89, when the target skinning speed is not greater thana predetermined skinning speed (No, block 3005), the method 3000 mayinclude activating a pressure boost system mounted to a skinning pipe toreduce a space (e.g., space 1810) adjacent the skinning pipe availablefor the flowable mixture to flow (block 3025). The method 3000 mayinclude starting the skinning process after activating the pressureboost system (block 3030). The method 3000 may include deactivating thepressure boost system to increase the space adjacent the skinning pipeavailable for the flowable mixture to flow after a pipe pressureincreases to a predetermined threshold pipe pressure (block 3035).

FIG. 90 is a flowchart illustrating an exemplary method 4000 ofcontrolling the skinning system 300. The method 4000 may be performed bythe skinning control system 410. The method 4000 may include determiningthat a target skinning speed (e.g., 6 mm/sec) is greater than apredetermined skinning speed (e.g., 5 mm/sec) (block 4005). The method4000 may also include starting the skinning process by increasing askinning speed incrementally in a plurality of steps or stages until thetarget skinning speed is reached (block 4010). For example, the method4000 may include skinning a first article at a skinning speed of 2mm/sec after starting the skinning process, and the skinning a secondarticles at a skinning speed of 4 mm/sec, and skinning a third articleat a skinning speed of 6 mm/sec.

FIG. 91 is a flowchart illustrating an exemplary method 4050 ofcontrolling the skinning system 300. The method 4050 may be performed bythe skinning control system 410. The method 4050 may include pushing, byan article feeding mechanism, an article into a skinning pipe to receivea flowable mixture (block 4055). The method 4050 may include pulling, bya transfer system (e.g., a vacuum system using a vacuum pressure), thearticle out of the skinning pipe as the article moves through the pipeto receive the flowable mixture (block 4060). The method 4050 mayinclude measuring, by a force sensor, a force between the articlefeeding mechanism and the transfer system (e.g., the vacuum system)(block 4065). The method 4050 may include determining, by a controlsystem, at least one of positions or speeds of the article feedingmechanism and the transfer system (e.g., the vacuum system) based on themeasured force (block 4070).

FIG. 92 is a flowchart illustrating an exemplary method 5000 ofdetecting a skin thickness of a skinned article in the skinning system300. The method 5000 may include applying an electrical current, using acircuit, to a portion of the flowable mixture coated onto an outersurface of an article (block 5005). The method 5000 may includemeasuring a voltage across a portion of the circuit (block 5010). Themethod 5000 may include determining, using a processor, the thickness ofthe flowable mixture coated on the article based on the measured voltageand a predetermined relationship between thicknesses and voltages (block5015).

FIG. 93 is a flowchart illustrating an exemplary method 5050 ofcontrolling the skinning system 300. The method 5050 may be performed bythe skinning control system 410. The method 5050 may include measuring,using at least one laser device, a variation in a dimension (e.g.,diameter) of one or more incoming unskinned articles (block 5055).Measuring the variation in the dimension may include measuring thedimension using at least one laser device, and determining the variationin the dimension using a controller or a control system, which receivessignals or data from the at least one laser device. The method 5050 mayinclude determining, using a feed forward controller, an adjustment to askinning speed or a pressure relief system position based on themeasured variation (block 5060). The method 5050 may includetransmitting a control signal to a skinning control system to adjust atleast one of the skinning speed or the pressure relief system position,based on an output from the feed forward controller (block 5065).

FIG. 94 is a flowchart illustrating an exemplary method 6000 ofcontrolling the skinning system 300. The method 6000 may be performed bythe skinning control system 410. The method 6000 may include measuring afirst dimension (e.g., diameter) of a first article prior to entering askinning pipe (block 6005). The method 6000 may include determining thatthe measured first dimension (e.g., diameter) is outside of apredetermined limit (block 6010). The method 6000 may include switchingfrom a first control scheme to a second control scheme (block 6015). Themethod 6000 may include measuring dimensions (e.g., diameters) of apredetermined number of subsequent articles following the first article(block 6020). The method 6000 may include determining that thedimensions (e.g., diameters) of the predetermined number of subsequentarticles are within the predetermined limit (block 6025). The method6000 may include switching from the second control scheme to the firstcontrol scheme (block 6030).

In addition to the above descriptions, the following descriptionssummarize various non-limiting embodiments disclosed herein.

According to a first embodiment, the present disclosure relates to asystem for delivering and applying a flowable mixture to an article. Thesystem may include a mixture delivery system. The mixture deliverysystem may include a mixer configured to mix a dry material and a fluidto produce the flowable mixture, and a pump disposed downstream of themixer and configured to pump the flowable mixture to a delivery line.The system may include a skinning system fluidly coupled with themixture delivery system through the delivery line, the skinning systemconfigured to receive the flowable mixture from the mixture deliverysystem through the delivery line and to apply the flowable mixture tothe article. The skinning system may include a skinning pipe configuredto receive the article and apply the flowable mixture to the article asthe article moves axially along an inner space of the skinning pipe. Theskinning system may include a manifold including a plurality of groovesconfigured to deliver the flowable mixture to the skinning pipe, and anarticle feeding mechanism configured to align the article with theskinning pipe and push the article into the inner space of the skinningpipe. The skinning system may include a transfer system configured tohold the article and move the article out of the skinning pipe as thearticle moves axially along the inner space of the skinning pipe toreceive the flowable mixture.

According to a second embodiment, the mixture delivery system of thefirst embodiment may further include a storage device coupled with themixer and configured to store the flowable mixture produced by themixer. The storage device may include a cone shaped structure configuredto store the flowable mixture, and a vibration device mounted to anouter surface of the cone shaped structure and configured to causevibration to the cone shaped structure when the flowable mixture isforced into the pump.

According to a third embodiment, the mixture delivery system of thefirst or second embodiment may further include a particle analyzerconfigured to measure a particle size distribution of the dry material.

According to a fourth embodiment, the mixture delivery system of thefirst or second embodiment may further include at least one sensorconfigured to measure at least one of a density, a flow rate, apressure, and a viscosity of the flowable mixture.

According to a fifth embodiment, the vibration device of the secondembodiment may be mounted to the outer surface at a rib of the coneshaped structure.

According to a sixth embodiment, the storage device of the second orfifth embodiment may include a vacuum system configured to withdraw airfrom the storage device.

According to a seventh embodiment, the storage device of the second orfifth embodiment may include a load cell configured to weigh at leastone of the storage device and the flowable mixture stored therein.

According to an eighth embodiment, the storage device of the second orfifth embodiment may include an auger disposed within the cone shapedstructure and configured to force the flowable mixture into the pump.

According to a ninth embodiment, the auger of the eighth embodiment mayinclude a helical screw blade configured to be in close proximity to aninner wall of the cone shaped structure without contacting the innerwall during operation.

According to a tenth embodiment, the mixture delivery system of thefirst, second, or fifth embodiment may further include a recirculationline configured to recirculate at least a portion of the flowablemixture from the delivery line to the storage device.

According to a eleventh embodiment, the mixture delivery system of thefirst, second, or fifth embodiment may further include a delivery valvedisposed within the delivery line and configured to control an amount ofthe flowable mixture directed to the skinning system.

According to a twelfth embodiment, the mixture delivery system of theeleventh embodiment may further include a purge line connected to aportion of the delivery line downstream of the pump and upstream of thedelivery valve, the purge line configured to direct the flowable mixtureout of the delivery line when the purge line is opened.

According to a thirteenth embodiment, the pump of the first, second, orfifth embodiment is a first pump, and the mixture delivery system of thefirst, second, or fifth embodiment may further include a fluiddispensing system configured to dispense the fluid to the mixer. Thefluid dispensing system may include a storage tank configured to storethe fluid, a second pump configured to pump the fluid from the storagetank, and a recirculation loop configured to recirculate the fluidpumped out of the storage tank by the pump back to the storage tank.

According to a fourteenth embodiment, the recirculation loop of thethirteenth embodiment may include a flow control valve configured tocontrol an amount of fluid flowing in the recirculation loop, and acontroller configured to control the flow control valve based on a speedof the second pump to maintain a substantially constant pressure withinthe recirculation loop.

According to a fifteenth embodiment, the fluid dispensing system of thefourteenth embodiment may include a plurality of distribution branchesconnected to the recirculation loop and configured to receive the fluidfrom the recirculation loop while the substantially constant pressure ismaintained within the recirculation loop.

According to a sixteenth embodiment, the article feeding mechanism ofthe first, second, or fifth embodiment may include a platen configuredto support the article placed thereon, and a centering mechanismconfigured to center the article placed on the platen.

According to a seventeenth embodiment, the centering mechanism of thesixteenth embodiment may include a plurality of centering devices eachcomprising a centering actuator configured to center the article.

According to an eighteenth embodiment, each centering device of theseventeenth embodiment may include an adjusting mechanism configured toadjust a position of the at least one centering actuator relative to theplaten.

According to a nineteenth embodiment, the at least one adjustingmechanism of the eighteenth embodiment may include a locating platehaving a plurality of holes, and a locating pin configured to engagewith one of the plurality of holes.

According to a twentieth embodiment, the adjusting mechanism of thenineteenth embodiment may include a support having at least one guidehole, a rod configured to slide within the at least one guide hole, anda bracket mounted to the support and having a hole configured to engagewith the locating pin to secure a position of the at least one centeringactuator relative to the platen.

According to a twenty-first embodiment, the centering actuator of thetwentieth embodiment may be mounted to at least one of the locatingplate and the rod.

According to a twenty-second embodiment, the at least one adjustingmechanism of the eighteenth embodiment may include a motor configured toadjust the position of the at least one centering actuator.

According to a twenty-third embodiment, the centering mechanism of thesixteenth embodiment may include at least one air knife configured toblow air toward at least one of an unskinned article and the platen.

According to a twenty-fourth embodiment, the article feeding mechanismof the first, second, or fifth embodiment may be mounted to a lowercarriage movable along a rail relative to the skinning pipe.

According to a twenty-fifth embodiment, the article feeding mechanismand the lower carriage of the twenty-fourth embodiment may be disposedbelow the skinning pipe in a vertical direction.

According to a twenty-sixth embodiment, the article feeding mechanism ofthe twenty-fifth embodiment may be configured to push the article intothe skinning pipe from below the skinning pipe in the verticaldirection.

According to a twenty-seventh embodiment, in the system of the first,second, or fifth embodiment, the article feeding mechanism may bemounted on a lower carriage, and the transfer system may be mounted onan upper carriage. The lower carriage and the upper carriage may bemounted on a vertical rail and may move along the vertical rail. Thelower carriage may be disposed below the skinning pipe, and the uppercarriage may be disposed above the skinning pipe.

According to a twenty-eighth embodiment, the article feeding mechanismof the sixteenth embodiment may include a flexure shaft configured tosupport the platen, the flexure shaft being deflectable while thearticle feeding mechanism pushes the article into the skinning pipe.

According to a twenty-ninth embodiment, the article feeding mechanism ofthe twenty-eighth embodiment may include a tilt limiter located adjacentthe flexure shaft and configured to limit deflection of the flexureshaft.

According to a thirtieth embodiment, the transfer system of the first,second, or fifth embodiment may be mounted to an upper carriage movablealong a rail relative to the skinning pipe.

According to a thirty-first embodiment, the upper carriage and thetransfer system of the thirtieth embodiment may be disposed above theskinning pipe in a vertical direction.

According to a thirty-second embodiment, the transfer system of thethirty-first embodiment may be configured to pull the article upward inthe vertical direction out of the skinning pipe.

According to a thirty-third embodiment, the transfer system of thefirst, second, or fifth embodiment may include a vacuum systemconfigured to generate a vacuum pressure within the article. The vacuumsystem may include a vacuum chuck configured to hold the article usingthe vacuum pressure, and pull the article out of the skinning pipe whileholding the article using the vacuum pressure.

According to a thirty-fourth embodiment, the vacuum chuck of thethirty-third embodiment may be a multi-zone vacuum chuck, each zonebeing independently controlled.

According to a thirty-fifth embodiment, the transfer system of thethirty-third embodiment may include a vacuum system configured togenerate multiple vacuum zones within more than one article. The vacuumsystem may be configured to hold the more than one article by a vacuumpressure and move the more than one article out of the skinning pipe.

According to a thirty-sixth embodiment, the system of the thirty-fifthembodiment may include a first spacer disposed at a bottom surface of afirst article to seal off a first vacuum zone, and a second spacerdisposed at a bottom surface of a second article to seal off a secondvacuum zone, a shape of the first spacer being different from a shape ofthe second spacer.

According to a thirty-seventh embodiment, the skinning system of thefirst, second, or fifth embodiment may include at least one force sensorconfigured to measure at least one force experienced by at least one ofthe transfer system and the article feeding mechanism.

According to a thirty-eighth embodiment, the skinning system of thethirty-seventh embodiment may include a control system configured tocontrol motions of the transfer system and the article feeding mechanismbased on the at least one force.

According to a thirty-ninth embodiment, the control system of thethirty-eighth embodiment may be configured to adjust at least one of aposition and a speed of at least one of the article feeding mechanismand the transfer system based on the at least one force.

According to a fortieth embodiment, the at least one force sensor of thethirty-seventh embodiment may include at least one first force sensorconfigured to measure a first force experienced by the transfer systemor an upper carriage to which the transfer system is mounted, and atleast one second force sensor configured to measure a second forceexperienced by the article feeding mechanism or a lower carriage towhich the article feeding mechanism is mounted.

According to a forty-first embodiment, in the system of thethirty-eighth embodiment, the transfer system may include a vacuumsystem configured to generate multiple vacuum zones, and the controlsystem may be configured to activate or deactivate one or more of themultiple vacuum zones based on the at least one force.

According to a forty-second embodiment, the skinning system of thefirst, second, or fifth embodiment may further include at least onelaser device disposed adjacent an inlet of the skinning pipe andconfigured to measure a dimension of an unskinned article, the dimensionincluding at least one of a diameter, a radius, a circumference, and anouter peripheral length.

According to a forty-third embodiment, the at least one laser device ofthe forty-second embodiment may include a plurality of laser devices,each laser devices including a laser unit and a camera.

According to a forty-fourth embodiment, the skinning system of thefirst, second, or fifth embodiment may further include at least onelaser device disposed adjacent an outlet of the skinning pipe andconfigured to monitor presence of a defect on a skinned article coatedwith the flowable mixture.

According to a forty-fifth embodiment, in the forty-fourth embodiment,the at least one laser device disposed adjacent the outlet of theskinning pipe may also be configured to detect the defect based onmonitoring the presence of the defect.

According to a forty-sixth embodiment, the skinning system of the first,second, or fifth embodiment may further include at least one laserdevice disposed adjacent an outlet of the skinning pipe and configuredto measure a dimension of a skinned article.

According to a forty-seventh embodiment, the dimension of theforty-sixth embodiment may include at least one of a diameter, a radius,a circumference, and an outer peripheral length.

According to a forty-eighth embodiment, the skinning system of thefirst, second, or fifth embodiment may further include at least onefirst laser device disposed adjacent an inlet of the skinning pipe andconfigured to measure a dimension of an unskinned article, and at leastone second laser device disposed adjacent an outlet of the skinning pipeand configured to measure a dimension of a skinned article which is theunskinned article applied with the flowable mixture at an outer surface.

According to a forty-ninth embodiment, the skinning system of theforty-eighth embodiment may also include a controller configured toreceive data regarding the dimension of the unskinned article and dataregarding the dimension of the skinned article, the dimension includingat least one of a diameter, a radius, a circumference, and an outerperipheral length. The controller may also be configured to calculate athickness of the flowable mixture applied to the outer surface of theunskinned article based on the dimensions of the unskinned article andthe skinned article.

According to a fiftieth embodiment, the dimension of the forty-eighthembodiment may include at least one of a diameter, a radius, acircumference, and an outer peripheral length.

According to a fifty-first embodiment, the skinning system of the first,second, or fifth embodiment may further include a frame structureincluding a rail disposed in a vertical direction. The manifold may bemounted to a middle portion of the frame structure, the article feedingmechanism may be mounted to a lower carriage, the lower carriage beingmounted to the rail below the manifold, and the transfer system may bemounted to an upper carriage, the upper carriage being mounted to therail above the manifold.

According to a fifty-second embodiment, the manifold of the first,second, or fifth embodiment may include a pressure adjustment systemconfigured to adjust a pressure of the flowable mixture adjacent theskinning pipe.

According to a fifty-third embodiment, the manifold of the fifty-secondembodiment may further include a ring mounted to a lower manifold pieceof the manifold and configured to move along the skinning pipe underactuation of the pressure adjustment system.

According to a fifty-fourth embodiment, the manifold of the first,second, or fifth embodiment may include a skin thickness sensor mountedto a wall of the skinning pipe and configured to measure a thickness ofthe flowable mixture on a skinned article.

According to a fifty-fifth embodiment, the skin thickness sensor of thefifty-fourth embodiment may include at least one conductor configured toapply a current to the flowable mixture on the skinned article, and aprobe body housing the at least one conductor.

According to a fifty-sixth embodiment, the manifold of the first,second, or fifth embodiment may include an upper manifold piece, and alower manifold piece joined together with the upper manifold piece.

According to a fifty-seventh embodiment, the manifold of the fifty-sixthembodiment may include a locating pin located in at least one of theupper manifold piece and the lower manifold piece, and a locatingcylinder located in at least one of the lower manifold piece and theupper manifold piece, the locating cylinder and the locating pinengaging with one another to join the upper manifold piece and the lowermanifold piece.

According to a fifty-eighth embodiment, the manifold of the first,second, or fifth embodiment may be mounted to a mounting bracket. Themanifold may include at least one locating pad for locating the manifoldon the mounting bracket.

According to a fifty-ninth embodiment, the manifold of the first,second, or fifth embodiment may be mounted to a mounting bracket. Themanifold may include at least one locating blocks for locating themanifold on the mounting bracket.

According to a sixtieth embodiment, the skinning pipe of the first,second, or fifth embodiment may include a wall having a plurality ofholes, and the grooves may be configured to deliver the flowable mixturefrom the manifold to the inner space of the skinning pipe through theholes.

According to a sixty-first embodiment, in the sixtieth embodiment, theflowable mixture of within the grooves may be pressurized.

According to a sixty-second embodiment, the plurality of grooves of thesixty-first embodiment may be configured to deliver the flowable mixtureto a circumference of the wall of the skinning pipe.

According to a sixty-third embodiment, the skinning system of the first,second, or fifth embodiment may include at least one robot configured toload or unload the article.

According to a sixty-fourth embodiment, the at least one robot of thesixty-third embodiment may include a loading robot and an unloadingrobot. The loading robot may include a vacuum chuck configured to holdand lift an unskinned article using a vacuum pressure, and the unloadingrobot may include at least one adjustable arm configured to receive askinned article.

According to a sixty-fifth embodiment, the unloading robot of thesixty-fourth embodiment may include a sensor configured to detect apresence of the skinned article on the at least one adjustable arm.

According to a sixty-sixth embodiment, the present disclosure relates toa system for delivering and applying a flowable mixture to an article.The system may include a mixture delivery system configured to producethe flowable mixture and deliver the flowable mixture. The mixturedelivery system may include a mixer configured to mix a dry material anda fluid to produce the flowable mixture, and a pump disposed downstreamof the mixer and configured to pump the flowable mixture to a deliveryline. The system may include a skinning system connected to the mixturedelivery system through the delivery line, and configured to receive theflowable mixture from the mixture delivery system, and apply theflowable mixture to the article. The skinning system may include askinning pipe configured to receive the article and apply the flowablemixture to the article as the article moves axially through the skinningpipe. The system may include a control system including a mixturecontrol system for controlling the mixture delivery system and askinning control system for controlling the skinning system. The mixturecontrol system may include a first feed forward controller configured todetermine an adjustment to an amount of the fluid to be added to themixer based on a variation relating to a particle size distribution ofthe dry material. The mixture control system may include at least onefirst feedback controller configured to determine at least one of ascrewfill ratio of the mixer and the amount of the fluid to be added tothe mixer, based on at least one of a measured density and a measuredviscosity of the flowable mixture. The skinning control system mayinclude a second feed forward controller configured to determine anadjustment to at least one of a delivery pressure set point, a returnpressure set point, a speed of the pump, a delivery valve position, aflow rate set point, a skinning speed, and a pressure relief systemposition, based on a variation relating to at least one of a measuredflow rate, the measured viscosity, or dimensions of incoming unskinnedarticles, the dimensions including at least one of a diameter, a radius,a circumference, and an outer peripheral length. The skinning controlsystem may include at least one second feedback controller configured todetermine at least one of a skinning pipe pressure set point, thedelivery pressure set point, the return pressure set point, the speed ofthe pump, the delivery valve position, and the flow rate set point,based on a result of monitoring presence of a defect on a skinnedarticle coated with the flowable mixture. The control system may includea communication unit configured to transmit a control signal to at leastone of the mixture delivery system and the skinning system based on anoutput from at least one of the first feed forward controller, thesecond feed forward controller, the at least one first feedbackcontroller, and the at least one second feedback controller.

According to a sixty-seventh embodiment, the present disclosure relatesto a system for delivering and applying a flowable mixture to anarticle. The system may include a mixture delivery system configured toproduce the flowable mixture and deliver the flowable mixture, and askinning system connected to the mixture delivery system, and configuredto receive the flowable mixture from the mixture delivery system, andapply the flowable mixture to the article. The system may include acontrol system configured to control the mixture delivery system and theskinning system. The control system may include a feed forwardcontroller configured to determine an adjustment to an amount of a fluidto be added to a mixer included in the mixture delivery system based ona variation relating to a particle size distribution of a dry material.The control system may include at least one feedback controllerconfigured to determine at least one of a skinning pipe pressure setpoint associated with the skinning system, a delivery pressure set pointassociated with the mixture delivery system, a return pressure set pointassociated with the mixture delivery system, a pump speed associatedwith the mixture delivery system, a delivery valve position associatedwith the mixture delivery system, and a flow rate set point associatedwith the mixture delivery system, based on a result of monitoringpresence of a defect on a skinned article coated with the flowablemixture at the skinning system.

According to a sixty-eighth embodiment, the sixty-seventh embodiment mayinclude a communication unit configured to transmit a control signal toat least one of the mixture delivery system and the skinning systembased on an output from at least one of the feed forward controller andthe at least one feedback controller to adjust at least one parameter ofat least one of the mixture delivery system and the skinning system.

According to a sixty-ninth embodiment, in the sixty-seventh embodiment,the at least one feedback controller may be at least one first feedbackcontroller. The system may include at least one second feedbackcontroller configured to determine at least one of a screwfill ratio ofthe mixer included in the mixture delivery system and the amount of thefluid to be added to the mixer, based on at least one of a measureddensity and a measured viscosity of the flowable mixture.

According to a seventieth embodiment, in the system of the sixty-seventhembodiment, the feed forward controller may be a first feed forwardcontroller. The system may include a second feed forward controllerconfigured to determine an adjustment to at least one of the deliverypressure set point, the return pressure set point, the pump speed, thedelivery valve position, the flow rate set point, a skinning speed, anda pressure relief system position, based on a variation relating to atleast one of a measured flow rate, the measured viscosity, or dimensionsof incoming unskinned articles, the dimensions including at least one ofa diameter, a radius, a circumference, and an outer peripheral length.

According to a seventy-first embodiment, the feed forward controller ofthe sixty-seventh embodiment may be an adaptive feed forward controller.

According to a seventy-second embodiment, the control system of thesixty-seventh embodiment may include an adjustment mechanism configuredto adjust a model used by the feed forward controller based on ameasured viscosity.

According to a seventy-third embodiment, the adjustment mechanism of theseventy-second embodiment may be configured to adjust the model used bythe feed forward controller based on the measured viscosity and thevariation in the particle size distribution.

According to a seventy-fourth embodiment, 66-73, the control system ofany of the sixty-sixth to the seventy-third embodiment may include areference model configured to determine a reference viscosity based onthe variation in the particle size distribution.

According to a seventy-fifth embodiment, the adjustment mechanism of theseventy-fourth embodiment may be configured to adjust the model used bythe feed forward controller based on the reference viscosity.

According to a seventy-sixth embodiment, the adjustment mechanism of theseventy-second or seventy-third embodiment may be configured to adjustthe model used by the feed forward controller based on the referenceviscosity, the measured viscosity, and the adjustment to the amount ofthe fluid to be added to the mixer.

According to a seventy-seventh embodiment, the at least one secondfeedback controller of the sixty-ninth embodiment may include a thirdfeedback controller configured to determine the screwfill ratio of themixer based on the measured density of the flowable mixture.

According to a seventy-eighth embodiment, the at least one secondfeedback controller of the sixty-ninth embodiment may include a thirdfeedback controller configured to determine the amount of the fluid tobe added to the mixer based on the measured viscosity.

According to a seventy-ninth embodiment, the at least one feedbackcontroller of the sixty-seventh embodiment may include a first feedbackcontroller configured to determine the pump speed based on a measuredreturn pressure.

According to an eightieth embodiment, the at least one feedbackcontroller of the seventy-ninth embodiment may include a second feedbackcontroller configured to determine at least one of the return pressureset point and the delivery pressure set point based on the measuredskinning pipe pressure. The first feedback controller may be configuredto determine the pump speed also based on at least one of the returnpressure set point and the delivery pressure set point.

According to an eighty-first embodiment, in the system of theeighty-first embodiment, monitoring the presence of the defect mayinclude detecting a type of the defect, and the at least one feedbackcontroller may include a third feedback controller configured todetermine the skinning pipe pressure set point based on the type ofdefect. The second feedback controller may be configured to determine atleast one of the return pressure set point and the delivery pressure setpoint also based on the skinning pipe pressure set point.

According to an eighty-second embodiment, the at least one feedbackcontroller of the sixty-seventh embodiment may include a first feedbackcontroller configured to determine at least one of the pump speed andthe delivery valve position based on the measured skinning pipepressure.

According to an eighty-third embodiment, in the system of theeighty-second embodiment, monitoring the presence of the defect mayinclude detecting a type of the defect, and the at least one feedbackcontroller may include a second feedback controller configured todetermine the skinning pipe pressure set point based on the type ofdefect. The first feedback controller may be configured to determine atleast one of the pump speed and the delivery valve position also basedon the skinning pipe pressure set point.

According to an eighty-fourth embodiment, the at least one feedbackcontroller of the sixty-seventh embodiment may include a first feedbackcontroller configured to determine the pump speed based on a measuredflow rate of the flowable mixture in the mixture delivery system.

According to an eighty-fifth embodiment, the at least one feedbackcontroller of the eighty-fourth embodiment may include a second feedbackcontroller configured to determine the flow rate set point based on askinning pipe pressure measured in the skinning system. The firstfeedback controller may be configured to determine the pump speed alsobased on the flow rate set point.

According to an eighty-sixth embodiment, in the system of theeighty-fifth embodiment, monitoring the presence of the defect mayinclude detecting a type of the defect, and the at least one feedbackcontroller may include a third feedback controller configured todetermine the skinning pipe pressure set point based on the type ofdefect. The second feedback controller may be configured to determinethe flow rate set point also based on the skinning pipe pressure setpoint.

According to an eighty-seventh embodiment, the at least one secondfeedback controller of the sixty-ninth embodiment may be configureddetermine a mixer speed based on at least one of a measured density anda measured viscosity of the flowable mixture.

According to an eighty-eighth embodiment, the second feed forwardcontroller of the seventieth embodiment may include a third feed forwardcontroller configured to determine an adjustment to at least one of thereturn pressure set point or the delivery pressure set point based onthe variation relating to at least one of the measured viscosity andmeasured flow rate.

According to an eighty-ninth embodiment, the second feed forwardcontroller of the seventieth embodiment may include a third feed forwardcontroller configured to determine an adjustment to at least one of thepump speed and the delivery valve position based on the variationrelating to at least one of the measured viscosity and the measured flowrate.

According to a ninetieth embodiment, the second feed forward controllerof the seventieth embodiment may include a third feed forward controllerconfigured to determine an adjustment to the flow rate set point basedon the variation relating to at least one of the measured viscosity andthe measured flow rate.

According to a ninety-first embodiment, the second feed forwardcontroller of the seventies embodiment may include a third feed forwardcontroller configured to determine an adjustment to the skinning speedbased on the variation relating to the dimensions of incoming unskinnedarticles measured in the skinning system.

According to a ninety-second embodiment, the second feed forwardcontroller of the seventieth embodiment may include a third feed forwardcontroller configured to determine an adjustment to the pressure reliefsystem position based on the variation relating to the dimensions ofincoming unskinned articles measured in the skinning system.

According to a ninety-third embodiment, the feedback controller of theninety-first or ninety-second embodiment may include a first feedbackcontroller configured to determine the skinning speed based on ameasured skinning pipe pressure.

According to a ninety-fourth embodiment, the feedback controller of theninety-second embodiment may include a first feedback controllerconfigured to determine the pressure relief system position based on ameasured skinning pipe pressure.

According to a ninety-fifth embodiment, the control system of theseventieth embodiment may be configured to switch between a firstskinning pipe pressure control scheme and a second skinning pipe controlscheme based on the dimensions of incoming unskinned articles measuredin the skinning system.

According to a ninety-sixth embodiment, in the sixty-ninth embodiment,at least one of the measured density and the measured viscosity may bemeasured in real time or near real time.

According to a ninety-seventh embodiment, the control system of theseventieth embodiment may be configured to receive real-time or nearreal-time measurements of at least one of a skinning pipe pressure, adelivery pressure, a return pressure, the pump speed, the delivery valveposition, the flow rate, the viscosity, the dimensions of the incomingunskinned articles, the skinning speed, or the pressure relief systemposition.

According to a ninety-eighth embodiment, the dimensions of theseventieth embodiment may include at least one of a diameter, a radius,a circumference, and an outer peripheral length.

According to a ninety-ninth embodiment, the present disclosure relatesto a method of delivering and applying a flowable mixture to an article.The method may include mixing a dry material with a fluid in a mixer toproduce a flowable mixture, and pumping the flowable mixture to askinning system through a delivery line, the skinning system including askinning pipe and an article feeding mechanism. The method may includealigning the article with the skinning pipe using the article feedingmechanism, pushing the article into an inner space of the skinning pipeusing the article feeding mechanism, delivering the flowable mixture tothe skinning pipe, and applying, using the skinning pipe, the flowablemixture to the article as the article moves axially along the innerspace of the skinning pipe. The method may include holding and movingthe article out of the skinning pipe as the article moves along theinner space of the skinning pipe to receive the flowable mixture.

According to a one hundredth embodiment, the method of the ninety-ninthembodiment may include placing the article on a platen. Aligning thearticle may include centering the article to align the article with theskinning pipe using a plurality of centering devices disposed around theplaten.

According to a one hundred and first embodiment, the method of the onehundredth embodiment may include adjusting positions of the centeringdevices based on a dimension of the article placed on the platen, thedimension including at least one of a diameter, a radius, acircumference, and an outer peripheral length.

According to a one hundred and second embodiment, the method of the onehundredth or one hundred and first embodiment may include blowing airtoward at least one of the platen and the article placed on the platento blow off debris.

According to a one hundred and third embodiment, in the method of any ofthe ninety-ninth embodiment to the one hundred and first embodiment,pushing the article into the inner space of the skinning pipe mayinclude pushing the article upward in a vertical direction from below aninlet of the skinning pipe.

According to a one hundred and fourth embodiment, the method of any ofthe ninety-ninth embodiment to the one hundred and first embodiment mayinclude generating a vacuum pressure within the article using a vacuumsystem.

According to a one hundred and fifth embodiment, the method of the onehundred and fourth embodiment may include generating more than onevacuum zone within more than one article.

According to a one hundred and sixth embodiment, in the method of theone hundred and fourth embodiment, holding and moving the article mayinclude holding and moving the article out of the skinning pipe usingthe vacuum pressure generated by the vacuum system.

According to a one hundred and seventh embodiment, in the method of theone hundred and sixth embodiment, holding and moving the article mayinclude holding and pulling the article upward out of the skinning pipe.

According to a one hundred and eighth embodiment, in the method of anyof the ninety-ninth to one hundred and first embodiment, pushing thearticle may include pushing the article using an article feedingmechanism. Holding and moving the article out of the skinning pipe mayinclude holding and moving the article using a transfer system. Themethod may include measuring at least one force experienced by at leastone of the transfer system and the article feeding mechanism, andcontrolling motions of the at least one of the transfer system and thearticle feeding mechanism based on the at least one force.

According to a one hundred and ninth embodiment, the method of the onehundred and eighth embodiment may include controlling motions of the atleast one of the transfer system and the article feeding mechanismcomprises adjusting at least one of a position and a speed of the atleast one of the transfer system and the article feeding mechanism basedon the at least one force.

According to a one hundred and tenth embodiment, the method of the onehundred and eighth embodiment may include generating multiple vacuumzones. Controlling motions of the at least one of the transfer systemand the article feeding mechanism may include activating or deactivatingone or more of the multiple vacuum zones based on the at least oneforce.

According to a one hundred and eleventh embodiment, the method of any ofthe ninety-ninth to one hundred and first embodiment may includemeasuring a dimension of at least one of an unskinned article and askinned article.

According to a one hundred and twelfth embodiment, in the method of theone hundred and eleventh embodiment, the dimension may include at leastone of a diameter, a radius, a circumference, and an outer peripherallength.

According to a one hundred and thirteenth embodiment, the method of anyof the ninety-ninth to one hundred and first embodiment may includemeasuring a dimension of an unskinned article, measuring a dimension ofa skinned article which is the unskinned article coated with theflowable mixture, and determining a thickness of the flowable mixture onthe skinned article based on the measured dimension of the unskinnedarticle and the dimension of the skinned article.

According to a one hundred and fourteenth embodiment, in the method ofthe one hundred and thirteenth embodiment, the dimension may include atleast one of a diameter, a radius, a circumference, and an outerperipheral length.

According to a one hundred and fifteenth embodiment, the method of anyof the ninety-ninth to one hundred and first embodiment may includemonitoring presence of a defect on a skinned article coated with theflowable mixture.

According to a one hundred and sixteenth embodiment, in the method ofthe one hundred and fifteenth embodiment, monitoring the presence of thedefect may include detecting a type of the defect.

According to a one hundred and seventeenth embodiment, the method of anyof the ninety-ninth to one hundred and first embodiment may includemoving a transfer system configured to hold and move the article out ofthe skinning pipe along a rail in a vertical direction above theskinning pipe, and moving an article feeding mechanism configured topush the article into the skinning pipe along the rail in the verticaldirection below the skinning pipe.

According to a one hundred and eighteenth embodiment, the method of anyof the ninety-ninth to one hundred and first embodiment may includeadjusting a pressure of the flowable mixture adjacent the skinning pipeusing a pressure adjustment system.

According to a one hundred and nineteenth embodiment, in the method ofthe one hundred and eighteenth embodiment, adjusting the pressure of theflowable mixture adjacent the skinning pipe using the pressureadjustment system may include moving a ring along the skinning pipe toadjust a space adjacent the skinning pipe available for the flowablemixture to flow.

According to a one hundred and twentieth embodiment, the method of anyof the ninety-ninth to one hundred and first embodiment may includemeasuring a thickness of the flowable mixture of a skinned article usinga skin thickness sensor.

According to a one hundred and twenty-first embodiment, in the method ofthe one hundred and twentieth embodiment, measuring the thickness mayinclude applying an electric current to the flowable mixture using acircuit, measuring a voltage across a portion of the circuit, anddetermining the thickness based on the measured voltage and apredetermined relationship between voltages and thicknesses.

According to a one hundred and twenty-second embodiment, the method ofany of the ninety-ninth to one hundred and first embodiment may includeloading an unskinned article onto a platen using a robot having a vacuumchuck configured to generate a vacuum pressure within the unskinnedarticle.

According to a one hundred and twenty-third embodiment, the method ofany of the ninety-ninth to one hundred and first embodiment may includeunloading a skinned article using a robot having an adjustable arm.

According to a one hundred and twenty-fourth embodiment, the method ofany of the ninety-ninth to one hundred and first embodiment may includegenerating multiple vacuum zones and holding and moving more than onearticle using the multiple vacuum zones.

According to a one hundred and twenty-fifth embodiment, the method ofthe one hundred and twenty-fourth embodiment may include using spacersdisposed at bottom surfaces of the more than one article to seal off themultiple vacuum zones, the spacers being alternately disposed at thebottom surfaces of the more than one article, at least two of thespacers having different shapes.

According to a one hundred and twenty-sixth embodiment, the method ofany of the ninety-ninth to one hundred and first embodiment may includemeasuring a particle size distribution of the dry material.

According to a one hundred and twenty-seventh embodiment, the method ofany of the ninety-ninth to one hundred and first embodiment may includemeasuring at least one of the density and viscosity of the flowablemixture.

According to a one hundred and twenty-eighth embodiment, in the methodof the one hundred and twenty-seventh embodiment, measuring the at leastone of the density and viscosity of the flowable mixture may includemeasuring the at least one of the density and viscosity in real time ornear real time.

According to a one hundred and twenty-ninth embodiment, the method ofthe one hundred and twenty-eighth embodiment may include determining atleast one of an amount of fluid to be added to the mixer and a screwfillratio of the mixer, based on at least one of the real-time or nearreal-time measurement of density and viscosity.

According to a one hundred and thirtieth embodiment, the presentdisclosure relates to a method of controlling a mixture delivery systemto deliver a flowable mixture and a skinning system to apply theflowable mixture to an article. The method may include mixing a drymaterial with a fluid in a mixer to produce the flowable mixture,pumping the flowable mixture to the skinning system through a deliveryline, measuring a particle size distribution of the dry material, anddetermining, using a first feed forward controller, an adjustment to anamount of the fluid to be added to the mixer based on a variationrelating to the particle size distribution. The method may also includemeasuring at least one of a density and a viscosity of the flowablemixture in the delivery line, determining, using at least one firstfeedback controller, at least one of the amount of fluid to be added tothe mixer and a screwfill ratio of the mixer, based on at least one ofthe measured density and the measured viscosity, and determining avariation relating to at least one of the measured viscosity, a flowrate, or dimensions of incoming unskinned articles, the dimensionsincluding at least one of a diameter, a radius, a circumference, and anouter peripheral length. The method may also include determining, usinga second feed forward controller, an adjustment to at least one of adelivery pressure set point, a return pressure set point, a speed of thepump, a delivery valve position, a flow rate set point, a skinningspeed, and a pressure relief system position, based on the variationrelating to at least one of the measured viscosity, the flow rate, orthe dimensions of the incoming unskinned articles. The method may alsoinclude measuring a skinning pipe pressure at a skinning pipe thatapplies the flowable mixture to the article, monitoring presence of adefect on a skinned article coated with the flowable mixture, anddetermining, using at least one second feedback controller, at least oneof a skinning pipe pressure set point, the delivery pressure set point,the return pressure set point, the speed of the pump, the delivery valveposition, and the flow rate set point, based on a result of monitoringthe presence of the defect on the skinned article. The method mayfurther include transmitting a control signal to at least one of themixture delivery system and the skinning system based on an output fromat least one of the first feed forward controller, the second feedforward controller, the at least one first feedback controller, and theat least one second feedback controller.

According to a one hundred and thirty-first embodiment, the presentdisclosure relates to a method of controlling a mixture delivery systemto deliver a flowable mixture and a skinning system to apply theflowable mixture to an article. The method may include mixing a drymaterial with a fluid in a mixer to produce the flowable mixture,pumping the flowable mixture to the skinning system through a deliveryline, and determining, using a feed forward controller, an adjustment toan amount of the fluid to be added to the mixer based on a variationrelating to a particle size distribution of the dry material. The methodmay also include determining, using at least one feedback controller, atleast one of a skinning pipe pressure set point, a delivery pressure setpoint, a return pressure set point, a pump speed, a delivery valveposition, and a flow rate set point, based on a result of monitoringpresence of a defect on a skinned article. The method may furtherinclude transmitting a control signal to at least one of the mixturedelivery system and the skinning system based on an output from at leastone of the feed forward controller and the at least one feedbackcontroller to adjust at least one parameter associated with at least oneof the mixture delivery system and the skinning system.

According to a one hundred and thirty-second embodiment, the method ofthe one hundred and thirty-first embodiment may include measuring theparticle size distribution of the dry material.

According to a one hundred and thirty-third embodiment, the method ofthe one hundred and thirty-first embodiment may include measuring atleast one of the density and viscosity of the flowable mixture.

According to a one hundred and thirty-fourth embodiment, in the methodof the one hundred and thirtieth or one hundred and thirty-firstembodiment, measuring the at least one of the density and viscosity ofthe flowable mixture may include measuring the at least one of thedensity and viscosity in real time or near real time.

According to a one hundred and thirty-fifth embodiment, the method ofthe one hundred and thirtieth or one hundred and thirty-first embodimentmay include determining at least one of the amount of fluid to be addedto the mixer and a screwfill ratio of the mixer, based on at least oneof the measured density and viscosity.

According to a one hundred and thirty-sixth embodiment, the method ofany of the one hundred and thirtieth to one hundred and thirty-thirdembodiment may include determining an adjustment to at least one of thedelivery pressure set point, the return pressure set point, the pumpspeed, the delivery valve position, the flow rate set point, a skinningspeed, and a pressure relief system position, based on a variationrelating to at least one of a measured flow rate, the measuredviscosity, or dimensions of incoming unskinned articles, the dimensionsincluding at least one of a diameter, a radius, a circumference, and anouter peripheral length.

According to a one hundred and thirty-seventh embodiment, the feedforward controller of any of the one hundred and thirtieth to onehundred and thirty-third embodiment may be an adaptive feed forwardcontroller.

According to a one hundred and thirty-eighth embodiment, the method ofany of the one hundred and thirtieth to one hundred and thirty-thirdembodiment may include adjusting a model used by the feed forwardcontroller based on a measured viscosity.

According to a one hundred and thirty-ninth embodiment, the method ofthe one hundred and thirty-eighth embodiment may include adjusting themodel used by the feed forward controller based on the measuredviscosity and the variation relating to the particle size distribution.

According to a one hundred and fortieth embodiment, the method of theone hundred and thirty-eighth embodiment may include determining areference viscosity based on the variation relating to the particle sizedistribution.

According to a one hundred and forty-first embodiment, the method of theone hundred and thirty-eighth embodiment may include adjusting the modelused by the feed forward controller based on the reference viscosity.

According to a one hundred and forty-second embodiment, the method ofthe one hundred and thirty-eighth embodiment may include adjusting themodel used by the feed forward controller based on the referenceviscosity, the measured viscosity, and the adjustment to the amount ofthe fluid to be added to the mixer.

According to a one hundred and forty-third embodiment, in the method ofany of the one hundred and thirtieth to one hundred and thirty-thirdembodiment, determining at least one of the screwfill ratio of the mixerand the amount of the fluid to be added to the mixer based on at leastone of the measured density and the measured viscosity may includedetermining the screwfill ratio of the mixer based on the measureddensity of the flowable mixture.

According to a one hundred and forty-fourth embodiment, in the method ofany of the one hundred and thirtieth to one hundred and thirty-thirdembodiment, determining at least one of the screwfill ratio of the mixerand the amount of the fluid to be added to the mixer based on at leastone of the measured density and the measured viscosity may includedetermining the amount of the fluid to be added to the mixer based onthe measured viscosity.

According to a one hundred and forty-fifth embodiment, the method of anyof the one hundred and thirtieth to one hundred and thirty-thirdembodiment may include determining a pump speed based on a measuredreturn pressure.

According to a one hundred and forty-sixth embodiment, the method of theone hundred and forty-fifth embodiment may include determining at leastone of the return pressure set point and the delivery pressure set pointbased on a measured skinning pipe pressure, and determining the pumpspeed also based on at least one of the return pressure set point andthe delivery pressure set point.

According to a one hundred and forty-seventh embodiment, in the methodof the one hundred and forty-sixth embodiment, monitoring the presenceof the defect may include detecting a type of the defect. The method mayinclude determining the skinning pipe pressure set point based on thetype of defect, and determining at least one of the return pressure setpoint and the delivery pressure set point also based on the skinningpipe pressure set point.

According to a one hundred and forty-eighth embodiment, the method ofany of the one hundred and thirtieth to one hundred and thirty-thirdembodiment may include determining at least one of the pump speed andthe delivery valve position based on the measured skinning pipepressure.

According to a one hundred and forty-ninth embodiment, in the method ofany of the one hundred and thirtieth to one hundred and thirty-thirdembodiment, monitoring the presence of the defect may include detectinga type of the defect. The method may include determining the skinningpipe pressure set point based on the type of defect, and determining atleast one of the pump speed and the delivery valve position also basedon the skinning pipe pressure set point.

According to a one hundred and fiftieth embodiment, the method of any ofthe one hundred and thirtieth to one hundred and thirty-third embodimentmay include determining the pump speed based on a measured flow rate ofthe flowable mixture in the mixture delivery system.

According to a one hundred and fifty-first embodiment, the method of anyof the one hundred and thirtieth to one hundred and thirty-thirdembodiment may include determining the flow rate set point based on askinning pipe pressure measured in the skinning system, and determiningthe pump speed also based on the flow rate set point.

According to a one hundred and fifty-second embodiment, in the method ofany of the one hundred and thirtieth to one hundred and thirty-thirdembodiment, monitoring the presence of the defect may include detectinga type of the defect. The method may include determining the skinningpipe pressure set point based on the type of defect, and determining theflow rate set point also based on the skinning pipe pressure set point.

According to a one hundred and fifty-third embodiment, the method of anyof the one hundred and thirtieth to one hundred and thirty-thirdembodiment may include determining a mixer speed based on at least oneof a measured density and a measured viscosity of the flowable mixture.

According to a one hundred and fifty-fourth embodiment, the method ofany of the one hundred and thirtieth to one hundred and thirty-thirdembodiment may include determining an adjustment to at least one of thereturn pressure set point and the delivery pressure set point based onthe variation relating to at least one of the measured viscosity andmeasured flow rate.

According to a one hundred and fifty-fifth embodiment, the method of anyof the one hundred and thirtieth to one hundred and thirty-thirdembodiment may include determining an adjustment to at least one of thepump speed and the delivery valve position based on the variationrelating to at least one of the measured viscosity and the measured flowrate.

According to a one hundred and fifty-sixth embodiment, the method of anyof the one hundred and thirtieth to one hundred and thirty-thirdembodiment may include determining an adjustment to the flow rate setpoint based on the variation relating to at least one of the measuredviscosity and the measured flow rate.

According to a one hundred and fifty-seventh embodiment, the method ofthe one hundred and thirty-sixth embodiment may include determining anadjustment to the skinning speed based on the variation relating to thedimensions of incoming unskinned articles measured in the skinningsystem.

According to a one hundred and fifty-eighth embodiment, the method ofthe one hundred and thirty-sixth embodiment may include determining anadjustment to the pressure relief system position based on the variationrelating to the dimensions of incoming unskinned articles measured inthe skinning system.

According to a one hundred and fifty-ninth embodiment, the method of anyof the one hundred and thirtieth to one hundred and thirty-thirdembodiment may include determining the skinning speed based on ameasured skinning pipe pressure.

According to a one hundred and sixtieth embodiment, the method of any ofthe one hundred and thirtieth to one hundred and thirty-third embodimentmay include determining the pressure relief system position based on ameasured skinning pipe pressure.

According to a one hundred and sixty-first embodiment, the method of theone hundred and thirty-sixth embodiment may include switching between afirst skinning pipe pressure control scheme and a second skinning pipecontrol scheme based on the dimensions of incoming unskinned articlesmeasured in the skinning system.

According to a one hundred and sixty-second embodiment, the method ofany of the one hundred and thirtieth to one hundred and thirty-thirdembodiment may include measuring in real-time or near real-time at leastone of a skinning pipe pressure, a delivery pressure, a return pressure,a speed of the pump, a delivery valve position, a flow rate, aviscosity, dimensions of the incoming unskinned articles, a skinningspeed, or a pressure relief system position.

According to a one hundred and sixty-third embodiment, in the method ofthe one hundred and sixty-second embodiment, the dimensions may includeat least one of a diameter, a radius, a circumference, and an outerperipheral length.

According to a one hundred and sixty-fourth embodiment, the presentdisclosure relates to a control system for controlling a mixturedelivery system and a skinning system. The control system may include amemory configured to store instructions, and a processor configured toexecute the instructions to perform a mixture control process using amixture control system and a skinning control process using a skinningcontrol system. The mixture control system may include a first feedforward controller configured to determine an adjustment to an amount ofa fluid to be added to a mixer based on a variation relating to aparticle size distribution of the dry material, and at least one firstfeedback controller configured to determine at least one of a screwfillratio of the mixer and the amount of the fluid to be added to the mixer,based on at least one of a measured density and a measured viscosity ofthe flowable mixture. The skinning control system may include a secondfeed forward controller configured to determine an adjustment to atleast one of a delivery pressure set point, a return pressure set point,a pump speed, a delivery valve position, a flow rate set point, askinning speed, and a pressure relief system position, based on avariation relating to at least one of a measured flow rate, the measuredviscosity, or dimensions of incoming unskinned articles, the dimensionsincluding at least one of a diameter, a radius, a circumference, and anouter peripheral length. The skinning control system may include atleast one second feedback controller configured to determine at leastone of a skinning pipe pressure set point, the delivery pressure setpoint, the return pressure set point, the pump speed, the delivery valveposition, and the flow rate set point, based on a result of monitoring adefect on a skinned article coated with the flowable mixture. Thecontrol system may include a communication unit configured to transmit acontrol signal to at least one of the mixture delivery system and theskinning system based on an output from at least one of the first feedforward controller, the second feed forward controller, the at least onefirst feedback controller, and the at least one second feedbackcontroller, to adjust at least one parameter associated with the mixturedelivery system or the skinning system.

According to a one hundred and sixty-fifth embodiment, the presentdisclosure relates to a control system for controlling a mixturedelivery system and a skinning system. The control system may include amemory configured to store instructions, and a processor configured toexecute the instructions to perform a control scheme configured tocontrol operations of at least one of the mixture delivery system andthe skinning system. The control scheme may include a feed forwardcontroller configured to determine an adjustment to an amount of a fluidto be added to a mixer producing a flowable mixture based on a variationrelating to a particle size distribution of the dry material. Thecontrol scheme may include at least one feedback controller configuredto determine at least one of a skinning pipe pressure set point, adelivery pressure set point, a return pressure set point, a pump speed,a delivery valve position, and a flow rate set point, based on a resultof monitoring a defect on a skinned article coated with the flowablemixture.

According to a one hundred and sixty-sixth embodiment, in the controlsystem of the one hundred and sixty-fifth embodiment, the at least onefeedback controller may be at least one first feedback controller. Thecontrol scheme may include at least one second feedback controllerconfigured to determine at least one of a screwfill ratio of a mixer andthe amount of the fluid to be added to the mixer, based on at least oneof a measured density and a measured viscosity of the flowable mixture.

According to a one hundred and sixty-seventh embodiment, in the controlsystem of the one hundred and sixty-fifth embodiment, the feed forwardcontroller may be a first feed forward controller. The control schememay include a second feed forward controller configured to determine anadjustment to at least one of the delivery pressure set point, thereturn pressure set point, the pump speed, the delivery valve position,the flow rate set point, a skinning speed, and a pressure relief systemposition, based on a variation relating to at least one of a measuredflow rate, the measured viscosity, or dimensions of incoming unskinnedarticles, the dimensions including at least one of a diameter, a radius,a circumference, and an outer peripheral length.

According to a one hundred and sixty-eighth embodiment, the controlsystem of the one hundred and sixty-fifth embodiment may include acommunication unit configured to transmit a control signal to at leastone of the mixture delivery system and the skinning system based on anoutput from at least one of the feed forward controller and the at leastone feedback controller, to adjust at least one parameter of at leastone of the mixture delivery system and the skinning system.

According to a one hundred and sixty-ninth embodiment, in the controlsystem of the one hundred and sixty-fifth embodiment, the feed forwardcontroller may be an adaptive feed forward controller.

According to a one hundred and seventieth embodiment, the control schemeof the one hundred and sixty-fifth embodiment may include an adjustmentmechanism configured to adjust a model used by the feed forwardcontroller based on a measured viscosity.

According to a one hundred and seventy-first embodiment, the adjustmentmechanism of the one hundred and seventieth embodiment may be configuredto adjust the model used by the feed forward controller based on themeasured viscosity and the variation relating to the particle sizedistribution.

According to a one hundred and seventy-second embodiment, in the onehundred and sixty-fourth or one hundred and seventieth embodiment, thecontrol scheme may include a reference model configured to determine areference viscosity based on the variation relating to the particle sizedistribution.

According to a one hundred and seventy-third embodiment, the adjustmentmechanism of the one hundred and seventy-second embodiment may beconfigured to adjust the model used by the feed forward controller basedon the reference viscosity.

According to a one hundred and seventy-fourth embodiment, the adjustmentmechanism of the one hundred and seventy-third embodiment may beconfigured to adjust the model used by the feed forward controller basedon the reference viscosity, the measured viscosity, and the adjustmentto the amount of the fluid to be added to the mixer.

According to a one hundred and seventy-fifth embodiment, the at leastone second feedback controller of the one hundred and sixty-sixthembodiment may include a third feedback controller configured todetermine the screwfill ratio of the mixer based on the measured densityof the flowable mixture.

According to a one hundred and seventy-sixth embodiment, the at leastone second feedback controller of the one hundred and sixty-sixthembodiment may include a third feedback controller configured todetermine the amount of the fluid to be added to the mixer based on themeasured viscosity.

According to a one hundred and seventy-seventh embodiment, the at leastone feedback controller of the one hundred and sixty-fifth embodimentmay include a first feedback controller configured to determine the pumpspeed based on a measured return pressure.

According to a one hundred and seventy-eighth embodiment, the at leastone feedback controller of the one hundred and seventy-seventhembodiment may include a second feedback controller configured todetermine at least one of the return pressure set point and the deliverypressure set point based on the measured skinning pipe pressure. Thefirst feedback controller may be configured to determine the pump speedalso based on at least one of the return pressure set point and thedelivery pressure set point.

According to a one hundred and seventy-ninth embodiment, in the controlsystem of the one hundred and seventy-eighth embodiment, monitoring thepresence of the defect may include detecting a type of the defect, andthe at least one feedback controller may include a third feedbackcontroller configured to determine the skinning pipe pressure set pointbased on the type of defect. The second feedback controller may beconfigured to determine at least one of the return pressure set pointand the delivery pressure set point also based on the skinning pipepressure set point.

According to a one hundred and eightieth embodiment, the at least onefeedback controller of the one hundred and sixty-fifth embodiment mayinclude a first feedback controller configured to determine at least oneof the pump speed and the delivery valve position based on the measuredskinning pipe pressure.

According to a one hundred and eighty-first embodiment, in the controlsystem of the one hundred and eightieth embodiment, monitoring thepresence of the defect may include detecting a type of the defect, andthe at least one feedback controller may include a second feedbackcontroller configured to determine the skinning pipe pressure set pointbased on the type of defect. The first feedback controller may beconfigured to determine at least one of the pump speed and the deliveryvalve position also based on the skinning pipe pressure set point.

According to a one hundred and eighty-second embodiment, the at leastone feedback controller of the one hundred and sixty-fifth embodimentmay include a first feedback controller configured to determine the pumpspeed based on a measured flow rate of the flowable mixture in themixture delivery system.

According to a one hundred and eighty-third embodiment, the at least onefeedback controller of the one hundred and eighty-second embodiment mayinclude a second feedback controller configured to determine the flowrate set point based on a skinning pipe pressure measured in theskinning system. The first feedback controller may be configured todetermine the pump speed also based on the flow rate set point.

According to a one hundred and eighty-fourth embodiment, in the controlsystem of the one hundred and eighty-third embodiment, monitoring thepresence of the defect may include detecting a type of the defect, andthe at least one feedback controller may include a third feedbackcontroller configured to determine the skinning pipe pressure set pointbased on the type of defect. The second feedback controller may beconfigured to determine the flow rate set point also based on theskinning pipe pressure set point.

According to a one hundred and eighty-fifth embodiment, the at least onesecond feedback controller of the one hundred and sixty-sixth embodimentmay be configured determine a mixer speed based on at least one of ameasured density and a measured viscosity of the flowable mixture.

According to a one hundred and eighty-sixth embodiment, the second feedforward controller of the one hundred and sixty-seventh embodiment mayinclude a third feed forward controller configured to determine anadjustment to at least one of the return pressure set point and thedelivery pressure set point based on the variation relating to at leastone of the measured viscosity and measured flow rate.

According to a one hundred and eighty-seventh embodiment, the secondfeed forward controller of the one hundred and sixty-seventh embodimentmay include a third feed forward controller configured to determine anadjustment to at least one of the pump speed and the delivery valveposition based on the variation relating to at least one of the measuredviscosity and the measured flow rate.

According to a one hundred and eighty-eighth embodiment, the second feedforward controller of the one hundred and sixty-seventh embodiment mayinclude a third feed forward controller configured to determine anadjustment to the flow rate set point based on the variation relating toat least one of the measured viscosity and the measured flow rate.

According to a one hundred and eighty-ninth embodiment, the second feedforward controller of the one hundred and sixty-seventh embodiment mayinclude a third feed forward controller configured to determine anadjustment to the skinning speed based on the variation relating to thedimensions of incoming unskinned articles measured in the skinningsystem.

According to a one hundred and ninetieth embodiment, the second feedforward controller of the one hundred and sixty-seventh embodiment mayinclude a third feed forward controller configured to determine anadjustment to the pressure relief system position based on the variationrelating to the dimensions of incoming unskinned articles measured inthe skinning system.

According to a one hundred and ninety-first embodiment, the feedbackcontroller of the one hundred and ninetieth embodiment may include afirst feedback controller configured to determine the skinning speedbased on a measured skinning pipe pressure.

According to a one hundred and ninety-second embodiment, the feedbackcontroller of the one hundred and ninetieth embodiment may include afirst feedback controller configured to determine the pressure reliefsystem position based on a measured skinning pipe pressure.

According to a one hundred and ninety-third embodiment, the controlsystem of the one hundred and sixty-seventh embodiment may be configuredto switch between a first skinning pipe pressure control scheme and asecond skinning pipe control scheme based on the dimensions of incomingunskinned articles measured in the skinning system.

According to a one hundred and ninety-fourth embodiment, in the controlsystem of the one hundred and sixty-sixth embodiment, at least one ofthe measured density and the measured viscosity is measured in real timeor near real time.

According to a one hundred and ninety-fifth embodiment, in the controlsystem of any of the one hundred and sixty-fourth or one hundred andsixty-fifth embodiment, the control system may receive real-time or nearreal-time measurements of at least one of a skinning pipe pressure, adelivery pressure, a return pressure, a speed of the pump, a deliveryvalve position, a flow rate, a viscosity, dimensions of the incomingunskinned articles, a skinning speed, or a pressure relief systemposition.

According to a one hundred and ninety-sixth embodiment, the dimensionsof the one hundred and ninety-fifth embodiment may include at least oneof a diameter, a radius, a circumference, and an outer peripherallength.

According to a one hundred and ninety-seventh embodiment, the presentdisclosure relates to a mixture delivery system for producing anddelivering a flowable mixture to a delivery line. The mixture deliverysystem may include a mixer configured to mix a dry material and a fluidto produce the flowable mixture, a storage device coupled with the mixerand configured to store the flowable mixture produced by the mixer, anda pump coupled with the storage device and configured to pump theflowable mixture from the storage device to the delivery line. Thestorage device may include a cone shaped structure configured to storethe flowable mixture, and a vibration device mounted to an outer surfaceof the cone shaped structure and configured to cause vibration to thecone shaped structure when the flowable mixture is forced into the pump.

According to a one hundred and ninety-eighth embodiment, mixturedelivery system of the one hundred and ninety-seventh embodiment mayinclude a particle analyzer configured to measure a particle sizedistribution of the dry material.

According to a one hundred and ninety-ninth embodiment, mixture deliverysystem of any of the one hundred and ninety-seventh or one hundred andninety-eighth embodiment may include at least one sensor configured tomeasure at least one of a density, a flow rate, a pressure, and aviscosity of the flowable mixture.

According to a two hundredth embodiment, in the mixture delivery systemof any of the one hundred and ninety-seventh or one hundred andninety-eighth embodiment, the vibration device may be mounted to theouter surface at a rib of the cone shaped structure.

According to a two hundred and first embodiment, in the mixture deliverysystem of any of the one hundred and ninety-seventh or one hundred andninety-eighth embodiment, the storage device may include a vacuum systemconfigured to withdraw air from the storage device.

According to a two hundred and second embodiment, in the mixturedelivery system of any of the one hundred and ninety-seventh or onehundred and ninety-eighth embodiment, the storage device may include aload cell configured to weigh at least one of the storage device and theflowable mixture stored therein.

According to a two hundred and third embodiment, in the mixture deliverysystem of any of the one hundred and ninety-seventh or one hundred andninety-eighth embodiment, the storage device may include an augerdisposed within the cone shaped structure and configured to force theflowable mixture into the pump.

According to a two hundred and fourth embodiment, the auger of the twohundred and third embodiment may include a helical screw bladeconfigured to be in close proximity to an inner wall of the cone shapedstructure without contacting the inner wall during operation.

According to a two hundred and fifth embodiment, the mixture deliverysystem of any of the one hundred and ninety-seventh or one hundred andninety-eighth embodiment may include a recirculation line configured torecirculate at least a portion of the flowable mixture from the deliveryline to the storage device.

According to a two hundred and sixth embodiment, the mixture deliverysystem of any of the one hundred and ninety-seventh or one hundred andninety-eighth embodiment may include a delivery valve disposed withinthe delivery line and configured to control an amount of the flowablemixture directed to the skinning system.

According to a two hundred and seventh embodiment, the mixture deliverysystem of any of the one hundred and ninety-seventh or one hundred andninety-eighth embodiment may include a purge line connected to a portionof the delivery line downstream of the pump and upstream of the deliveryvalve, the purge line configured to direct the flowable mixture out ofthe delivery line when the purge line is opened.

According to a two hundred and eighth embodiment, in the mixturedelivery system of any of the one hundred and ninety-seventh or onehundred and ninety-eighth embodiment, the pump may be a first pump. Themixture delivery system may include a fluid dispensing system configuredto dispense the fluid to the mixer. The fluid dispensing system mayinclude a storage tank configured to store the fluid, a second pumpconfigured to pump the fluid from the storage tank, and a recirculationloop configured to recirculate the fluid pumped out of the storage tankby the pump back to the storage tank.

According to a two hundred and ninth embodiment, the recirculation loopof the two hundred and eighth embodiment may include a flow controlvalve configured to control an amount of fluid flowing in therecirculation loop, and a controller configured to control the flowcontrol valve based on a speed of the second pump to maintain asubstantially constant pressure within the recirculation loop.

According to a two hundred and tenth embodiment, the fluid dispensingsystem of the two hundred and ninth embodiment may include a pluralityof distribution branches connected to the recirculation loop andconfigured to receive the fluid from the recirculation loop while thesubstantially constant pressure is maintained within the recirculationloop.

According to a two hundred and eleventh embodiment, the presentdisclosure relates to a mixture delivery system for producing anddelivering a flowable mixture to a delivery line. The mixture deliverysystem may include a mixer configured to mixing a dry material and afluid to produce the flowable mixture, a storage device coupled with themixer and configured to store the flowable mixture produced by themixer, and a pump coupled with the storage device and configured to pumpthe flowable mixture from the storage device to the delivery line, thedelivery line leading to a skinning system configured to apply theflowable mixture to an article. The mixture delivery system may alsoinclude a recirculation line configured to recirculate a portion of theflowable mixture from the delivery line back to the storage device. Thestorage device may include a port connected with the recirculation linefor receiving the recirculated portion of the flowable mixture.

According to a two hundred and twelfth embodiment, the mixture deliverysystem of the two hundred and eleventh embodiment may include a particleanalyzer configured to measure a particle size distribution of the drymaterial.

According to a two hundred and thirteenth embodiment, mixture deliverysystem of any of the two hundred and eleventh or two hundred and twelfthembodiment may include at least one sensor configured to measure atleast one of a density, a flow rate, a pressure, and a viscosity of theflowable mixture.

According to a two hundred and fourteenth embodiment, the storage deviceof any of the two hundred and eleventh or two hundred and twelfthembodiment may include a cone shaped structure configured to store theflowable mixture, and a vibration device mounted to an outer surface ofthe cone shaped structure and configured to cause vibration to the coneshaped structure when the flowable mixture is forced into the pump.

According to a two hundred and fifteenth embodiment, the vibrationdevice of the two hundred and fourteenth embodiment may be mounted tothe outer surface at a rib of the cone shaped structure.

According to a two hundred and sixteenth embodiment, the storage deviceof any of the two hundred and eleventh or two hundred and twelfthembodiment may include a vacuum system configured to withdraw air fromthe storage device.

According to a two hundred and seventeenth embodiment, the storagedevice of any of the two hundred and eleventh or two hundred and twelfthembodiment may include a load cell configured to weigh at least one ofthe storage device and the flowable mixture stored therein.

According to a two hundred and eighteenth embodiment, the storage deviceof any of the two hundred and eleventh or two hundred and twelfthembodiment may include an auger disposed within the cone shapedstructure and configured to force the flowable mixture into the pump.

According to a two hundred and nineteenth embodiment, the auger of thetwo hundred and eighteenth embodiment may include a helical screw bladeconfigured to be in close proximity to an inner wall of the cone shapedstructure without contacting the inner wall during operation.

According to a two hundred and twentieth embodiment, the mixturedelivery system of any of the two hundred and eleventh or two hundredand twelfth embodiment may include a delivery valve disposed within thedelivery line and configured to control an amount of the flowablemixture directed to the skinning system.

According to a two hundred and twenty-first embodiment, the mixturedelivery system of the two hundred and twentieth embodiment may includea purge line connected to a portion of the delivery line downstream ofthe pump and upstream of the delivery valve, the purge line configuredto direct the flowable mixture out of the delivery line when the purgeline is opened.

According to a two hundred and twenty-second embodiment, in the mixturedelivery system of any of the two hundred and eleventh or two hundredand twelfth embodiment, the pump may be a first pump, and the mixturedelivery system may include a fluid dispensing system configured todispense the fluid to the mixer. The fluid dispensing system may includea storage tank configured to store the fluid, a second pump configuredto pump the fluid from the storage tank, and a recirculation loopconfigured to recirculate the fluid pumped out of the storage tank bythe pump back to the storage tank.

According to a two hundred and twenty-third embodiment, therecirculation loop of the two hundred and twenty-second embodiment mayinclude a flow control valve configured to control an amount of fluidflowing in the recirculation loop. The fluid dispensing system mayinclude a controller configured to control the flow control valve basedon a speed of the second pump to maintain a substantially constantpressure within the recirculation loop.

According to a two hundred and twenty-fourth embodiment, the fluiddispensing system of the two hundred and twenty-third embodiment mayinclude a plurality of distribution branches connected to therecirculation loop and configured to receive the fluid from therecirculation loop while the substantially constant pressure ismaintained within the recirculation loop.

According to a two hundred and twenty-fifth embodiment, the presentdisclosure relates to a mixture delivery system for producing anddelivering a flowable mixture to a delivery line. The mixture deliverysystem may include a mixer configured to mixing a dry material and afluid to produce the flowable mixture, a storage device coupled with themixer and configured to store the flowable mixture produced by themixer, and a pump coupled with the storage device and configured to pumpthe flowable mixture from the storage device to the delivery lineleading to a skinning system configured to apply the flowable mixture toan article. The mixture delivery system may include a delivery valvedisposed within the delivery line and configured to control an amount offlowable mixture flowing in the delivery line, and a purge line fluidlycoupled to the delivery line upstream of the delivery valve, the purgeline configured to purge the flowable mixture out of the mixturedelivery system when at least one property of the flowable mixture doesnot meet a target requirement.

According to a two hundred and twenty-sixth embodiment, the mixturedelivery system of the two hundred and twenty-fifth embodiment mayinclude a particle analyzer configured to measure a particle sizedistribution of the dry material.

According to a two hundred and twenty-seventh embodiment, the mixturedelivery system of any of the two hundred and twenty-fifth or twohundred and twenty-sixth embodiment may include at least one sensorconfigured to measure at least one of a density, a flow rate, apressure, and a viscosity of the flowable mixture.

According to a two hundred and twenty-eighth embodiment, the mixturedelivery system of any of the two hundred and twenty-fifth or twohundred and twenty-sixth embodiment may include a storage deviceconfigured to store the flowable mixture produced by the mixer. Thestorage device may include a cone shaped structure for storing theflowable mixture, and a vibration device mounted to an outer surface ofthe cone shaped structure and configured to cause vibration to the coneshaped structure when the flowable mixture is forced into the pump.

According to a two hundred and twenty-ninth embodiment, the vibrationdevice of the two hundred and twenty-eighth embodiment may be mounted tothe outer surface at a rib of the cone shaped structure.

According to a two hundred and thirtieth embodiment, the storage deviceof the two hundred and twenty-eighth embodiment may include a vacuumsystem configured to withdraw air from the storage device.

According to a two hundred and thirty-first embodiment, the storagedevice of the two hundred and twenty-eighth embodiment may include aload cell configured to weigh at least one of the storage device and theflowable mixture stored therein.

According to a two hundred and thirty-second embodiment, the storagedevice of the two hundred and twenty-eighth embodiment may include anauger disposed within the cone shaped structure and configured to forcethe flowable mixture into the pump.

According to a two hundred and thirty-third embodiment, the auger of thetwo hundred and thirty-second embodiment may include a helical screwblade configured to be in close proximity to an inner wall of the coneshaped structure without contacting the inner wall during operation.

According to a two hundred and thirty-fourth embodiment, in the mixturedelivery system of any of the two hundred and twenty-fifth or twohundred and twenty-sixth embodiment, the pump may be a first pump, andthe mixture delivery system may include a fluid dispensing systemconfigured to dispense the fluid to the mixer. The fluid dispensingsystem may include a storage tank configured to store the fluid, asecond pump configured to pump the fluid from the storage tank, and arecirculation loop configured to recirculate the fluid pumped out of thestorage tank by the pump back to the storage tank.

According to a two hundred and thirty-fifth embodiment, therecirculation loop of the two hundred and thirty-fourth embodiment mayinclude a flow control valve configured to control an amount of fluidflowing in the recirculation loop. The fluid dispensing system mayinclude a controller configured to control the flow control valve basedon a speed of the second pump to maintain a substantially constantpressure within the recirculation loop.

According to a two hundred and thirty-sixth embodiment, the fluiddispensing system of the two hundred and thirty-fifth embodiment mayinclude a plurality of distribution branches connected to therecirculation loop and configured to receive the fluid from therecirculation loop while the substantially constant pressure ismaintained within the recirculation loop.

According to a two hundred and thirty-seventh embodiment, the presentdisclosure relates to a storage device for storing a flowable mixture.The storage device may include a cone shaped structure configured tostore the flowable mixture, an auger disposed within the cone shapedstructure and configured to drive the flowable mixture to a pumpconnected to a lower portion of the cone shaped structure, and avibration device attached to an outer surface of the cone shapedstructure, the vibration device configured to vibrate the cone-shapedstructure to aid in moving the flowable mixture to the auger.

According to a two hundred and thirty-eighth embodiment, the vibrationdevice of the two hundred and thirty-seventh embodiment may be mountedto the outer surface at a rib of the cone shaped structure.

According to a two hundred and thirty-ninth embodiment, the storagedevice of any of the two hundred and thirty-seventh or two hundred andthirty-eighth embodiment may include a vacuum system configured towithdraw air from the storage device.

According to a two hundred and fortieth embodiment, the storage deviceof any of the two hundred and thirty-seventh or two hundred andthirty-eighth embodiment may include a load cell configured to weigh atleast one of the storage device and the flowable mixture stored therein.

According to a two hundred and forty-first embodiment, the auger of thetwo hundred and fortieth embodiment may include a helical screw bladeconfigured to be in close proximity to an inner wall of the cone shapedstructure without contacting the inner wall during operation.

According to a two hundred and forty-second embodiment, the presentdisclosure relates to a fluid dispensing system for delivering a fluidto a plurality of distribution branches. The fluid dispensing system mayinclude a storage tank configured to store the fluid, a pump configuredto pump the fluid from the storage tank to recirculate within arecirculation loop, the recirculation loop directing a portion of thefluid pumped out of the storage tank back to the storage tank, and aplurality of distribution branches connected to the recirculation loopand configured to receive fluid from the recirculation loop. The fluiddispensing system may include a flow control valve disposed in therecirculation loop and configured to control an amount of fluid flowwithin the recirculation loop, and a controller configured to adjust aposition of the flow control valve based on a speed of the pump tomaintain a substantially constant pressure within the recirculation loopwhile the fluid is delivered to the plurality of distribution branches.

According to a two hundred and forty-third embodiment, the presentdisclosure relates to a mixture delivery system for producing anddelivering a flowable mixture to a delivery line. The mixture deliverysystem may include a particle analyzer configured to measure a particlesize distribution of a dry material, a mixer configured to mix the drymaterial and a fluid to produce the flowable mixture, and a pumpdisposed downstream of the mixer and configured to pump the flowablemixture produced by the mixer to the delivery line. The mixture deliverysystem may include at least one sensor configured to measure at leastone of a density and a viscosity of the flowable mixture, and a mixturecontrol system including a communication unit configured to receive datarelating to the measured particle size distribution from the particleanalyzer, and receive data relating to the measured density or themeasured viscosity from the at least one sensor. The mixture controlsystem may include a feed forward controller configured to determine anadjustment to an amount of the fluid to be added to the mixer based on avariation relating to the measured particle size distribution, and atleast one feedback controller configured to determine at least one of ascrewfill ratio of the mixer and the amount of the fluid to be added tothe mixer, based on at least one of the measured density and themeasured viscosity. The communication unit may be further configured totransmit a control signal to at least one of the mixer and the pumpbased on an output from at least one of the feed forward controller andthe at least one feedback controller.

According to a two hundred and forty-fourth embodiment, the presentdisclosure relates to a mixture delivery system for producing anddelivering a flowable mixture to a delivery line. The mixture deliverysystem may include a mixer configured to mix the dry material and afluid to produce the flowable mixture, a pump disposed downstream of themixer and configured to pump the flowable mixture produced by the mixerto the delivery line, and a mixture control system including a feedforward controller configured to determine an adjustment to an amount ofthe fluid to be added to the mixer based on a variation relating to ameasured particle size distribution. The mixture control system mayinclude at least one feedback controller configured to determine atleast one of a screwfill ratio of the mixer and the amount of the fluidto be added to the mixer, based on at least one of a measured densityand a measured viscosity, and a communication unit configured totransmit a control signal to at least one of the mixer and the pumpbased on an output from at least one of the feed forward controller andthe at least one feedback controller to adjust at least one parameter ofat least one of the mixer and the pump.

According to a two hundred and forty-fifth embodiment, the mixturedelivery system of the two hundred and forty-fourth embodiment mayinclude a particle analyzer configured to measure the particle sizedistribution of the dry material.

According to a two hundred and forty-sixth embodiment, the mixturedelivery system of any of the two hundred and forty-fourth or twohundred and forty-fifth embodiment at may include least one sensorconfigured to measure at least one of the density and the viscosity ofthe flowable mixture.

According to a two hundred and forty-seventh embodiment, the at leastone sensor of the two hundred and forty-sixth embodiment may beconfigured to measure the at least one of the density and the viscosityin real time or near real time.

According to a two hundred and forty-eighth embodiment, thecommunication unit of the two hundred and forty-sixth embodiment may beconfigured to receive data relating to the measured particle sizedistribution from the particle analyzer, and data relating to themeasured density or the measured viscosity from the at least one sensor.

According to a two hundred and forty-ninth embodiment, the feed forwardcontroller of any of the two hundred and forty-fourth or two hundred andforty-fifth embodiment may be an adaptive feed forward controller.

According to a two hundred and fiftieth embodiment, the mixture controlsystem of any of the two hundred and forty-fourth or two hundred andforty-fifth embodiment may include an adjustment mechanism configured toadjust a model used by the feed forward controller based on a measuredviscosity.

According to a two hundred and fifty-first embodiment, the adjustmentmechanism of the two hundred and fiftieth embodiment may be configuredto adjust the model used by the feed forward controller based on themeasured viscosity and the variation relating to the particle sizedistribution.

According to a two hundred and fifty-second embodiment, the mixturecontrol system of any of the two hundred and forty-fourth or two hundredand forty-fifth embodiment may include a reference model configured todetermine a reference viscosity based on the variation relating to theparticle size distribution.

According to a two hundred and fifty-third embodiment, the adjustmentmechanism of the two hundred and fifty-second embodiment may beconfigured to adjust the model used by the feed forward controller basedon the reference viscosity.

According to a two hundred and fifty-fourth embodiment, the adjustmentmechanism of the two hundred and fifty-third embodiment may beconfigured to adjust the model used by the feed forward controller basedon the reference viscosity, the measured viscosity, and the adjustmentto the amount of the fluid to be added to the mixer.

According to a two hundred and fifty-fifth embodiment, the at least onefeedback controller of any of the two hundred and forty-fourth or twohundred and forty-fifth embodiment may be configured to determine thescrewfill ratio of the mixer based on the measured density of theflowable mixture.

According to a two hundred and fifty-sixth embodiment, the at least onefeedback controller of any of the two hundred and forty-fourth or twohundred and forty-fifth embodiment may be configured to determine theamount of the fluid to be added to the mixer based on the measuredviscosity.

According to a two hundred and fifty-seventh embodiment, the at leastone feedback controller of any of the two hundred and forty-fourth ortwo hundred and forty-fifth embodiment may be configured to determine apump speed based on a measured return pressure.

According to a two hundred and fifty-eighth embodiment, the at least onefeedback controller of any of the two hundred and forty-fourth or twohundred and forty-fifth embodiment may be configured to determine a pumpspeed based on a measured flow rate of the flowable mixture in themixture delivery system.

According to a two hundred and fifty-ninth embodiment, the at least onefeedback controller of any of the two hundred and forty-fourth or twohundred and forty-fifth embodiment may be configured to determine amixer speed based on at least one of a measured density and a measuredviscosity of the flowable mixture.

According to a two hundred and sixtieth embodiment, the at least onefeedback controller of any of the two hundred and forty-fourth or twohundred and forty-fifth embodiment may be configured to determine thescrewfill ratio of the mixer based on the measured density.

According to a two hundred and sixty-first embodiment, the at least onefeedback controller of any of the two hundred and forty-fourth or twohundred and forty-fifth embodiment may be configured to determine aspeed the mixer based on the measured density.

According to a two hundred and sixty-second embodiment, the at least onefeedback controller of any of the two hundred and forty-fourth or twohundred and forty-fifth embodiment may be configured to determine theamount of the fluid to be added to the mixer based on the measuredviscosity.

According to a two hundred and sixty-third embodiment, the feed forwardcontroller of any of the two hundred and forty-fourth or two hundred andforty-fifth embodiment may be configured to determine an adjustment toat least one of the return pressure set point and the delivery pressureset point based on the variation relating to at least one of themeasured viscosity and measured flow rate.

According to a two hundred and sixty-fourth embodiment, the at least onefeedback controller of any of the two hundred and forty-fourth or twohundred and forty-fifth embodiment may be configured to determine anadjustment to at least one of the pump speed and the delivery valveposition based on the variation relating to at least one of the measuredviscosity and the measured flow rate.

According to a two hundred and sixty-fifth embodiment, the at least onefeedback controller of any of the two hundred and forty-fourth or twohundred and forty-fifth embodiment may be configured to determine anadjustment to the flow rate set point based on the variation relating toat least one of the measured viscosity and the measured flow rate.

According to a two hundred and sixty-sixth embodiment, the presentdisclosure relates to a method of controlling at least one property of aflowable mixture produced by a mixture delivery system. The method mayinclude mixing a dry material and a fluid in a mixer to produce theflowable mixture, pumping the flowable mixture to a delivery line, anddetermining, using a feed forward controller, an adjustment to an amountof the fluid to be added to the mixer based on a variation relating to ameasured particle size distribution. The method may also includedetermining, using at least one feedback controller, at least one of ascrewfill ratio of the mixer and the amount of the fluid to be added tothe mixer, based on at least one of a measured density and a measuredviscosity, and transmitting a control signal to the mixer to adjust atleast one of the amount of fluid to be added to the mixer and thescrewfill ratio of the mixer, based on an output of at least one of thefeed forward controller and the at least one feedback controller.

According to a two hundred and sixty-seventh embodiment, the method ofthe two hundred and sixty-sixth embodiment may include measuring aparticle size distribution of the dry material.

According to a two hundred and sixty-eighth embodiment, the method ofany of the two hundred and sixty-sixth or two hundred and sixty-seventhembodiment may include measuring at least one of the density andviscosity of the flowable mixture.

According to a two hundred and sixty-ninth embodiment, in the method ofthe two hundred and sixty-eighth embodiment, measuring the at least oneof the density or viscosity of the flowable mixture may includemeasuring the at least one of the density and viscosity in real time ornear real time.

According to a two hundred and seventieth embodiment, the method of thetwo hundred and sixty-ninth embodiment may include determining at leastone of the amount of fluid to be added to the mixer and a screwfillratio of the mixer, based on at least one of the real-time or nearreal-time measurement of density and viscosity.

According to a two hundred and seventy-first embodiment, the method ofany of the two hundred and sixty-sixth or two hundred and sixty-seventhembodiment may include adjusting a model used by the feed forwardcontroller based on a measured viscosity.

According to a two hundred and seventy-second embodiment, the method ofthe two hundred and seventy-first embodiment may include adjusting themodel used by the feed forward controller based on the measuredviscosity and the variation relating to the particle size distribution.

According to a two hundred and seventy-third embodiment, the method ofthe two hundred and seventy-second embodiment may include determining areference viscosity based on the variation relating to the particle sizedistribution.

According to a two hundred and seventy-fourth embodiment, the method ofthe two hundred and seventy-third embodiment may include adjusting themodel used by the feed forward controller based on the referenceviscosity.

According to a two hundred and seventy-fifth embodiment, the method ofthe two hundred and seventy-third embodiment may include adjusting themodel used by the feed forward controller based on the referenceviscosity, the measured viscosity, and the adjustment to the amount ofthe fluid to be added to the mixer.

According to a two hundred and seventy-sixth embodiment, in the methodof any of the two hundred and sixty-sixth or two hundred andsixty-seventh embodiment, determining at least one of the screwfillratio of the mixer and the amount of the fluid to be added to the mixerbased on at least one of the measured density and the measured viscositymay include determining the screwfill ratio of the mixer based on themeasured density of the flowable mixture.

According to a two hundred and seventy-seventh embodiment, in the methodof any of the two hundred and sixty-sixth or two hundred andsixty-seventh embodiment, determining at least one of the screwfillratio of the mixer and the amount of the fluid to be added to the mixerbased on at least one of the measured density and the measured viscositymay include determining the amount of the fluid to be added to the mixerbased on the measured viscosity.

According to a two hundred and seventy-eighth embodiment, the method ofany of the two hundred and sixty-sixth or two hundred and sixty-seventhembodiment may include determining a pump speed based on a measuredreturn pressure.

According to a two hundred and seventy-ninth embodiment, the method ofthe two hundred and seventy-eighth embodiment may include determiningthe pump speed based on a measured flow rate of the flowable mixture inthe mixture delivery system.

According to a two hundred and eightieth embodiment, the method of anyof the two hundred and sixty-sixth or two hundred and sixty-seventhembodiment may include determining a mixer speed based on at least oneof the measured density and the measured viscosity of the flowablemixture.

According to a two hundred and eighty-first embodiment, the method ofany of the two hundred and sixty-sixth or two hundred and sixty-seventhembodiment may include determining an adjustment to at least one of thereturn pressure set point and the delivery pressure set point based onthe variation relating to at least one of the measured viscosity and ameasured flow rate.

According to a two hundred and eighty-second embodiment, the method ofany of the two hundred and sixty-sixth or two hundred and sixty-seventhembodiment may include determining an adjustment to at least one of thepump speed and the delivery valve position based on the variationrelating to at least one of the measured viscosity and a measured flowrate.

According to a two hundred and eighty-third embodiment, the method ofany of the two hundred and sixty-sixth or two hundred and sixty-seventhembodiment may include determining an adjustment to the flow rate setpoint based on the variation relating to at least one of the measuredviscosity and a measured flow rate.

According to a two hundred and eighty-fourth embodiment, the presentdisclosure relates to a method of delivering a fluid to a plurality ofdistribution branches. The method may include pumping, using a pump, thefluid from a storage tank to recirculate within a recirculation loop,the recirculation loop directing a portion of the fluid pumped out ofthe storage tank back to the storage tank. The method may includemeasuring a pressure in the recirculation loop, and adjusting a positionof a flow control valve disposed within the recirculation loop based onat least one of a speed of the pump and the measured pressure tomaintain a substantially constant pressure within the recirculation loopwhile the fluid is delivered to the plurality of distribution branches.

According to a two hundred and eighty-fifth embodiment, the presentdisclosure relates to a method of producing and delivering a highlyviscous mixture to a skinning system. The method may includecontinuously mixing a dry material and a fluid to produce the highlyviscous mixture, the highly viscous mixture having a viscosity ofgreater than 1 million centipoises, storing the highly viscous mixturewithin a storage device, and continuously pumping the highly viscousmixture from the storage device to a delivery line leading to theskinning system at a flow rate ranging from 50 pounds/hour to 300pounds/hour. The method may include continuously recirculating a portionof the highly viscous mixture from the delivery line back to the storagedevice through a recirculation line.

According to a two hundred and eighty-sixth embodiment, the presentdisclosure relates to a skinning system for applying a flowable mixtureto an article. The skinning system may include a skinning pipeconfigured to receive the article and apply the flowable mixture to thearticle as the article moves axially along an inner space of theskinning pipe, and a manifold including a plurality of groovesconfigured to deliver the flowable mixture to the skinning pipe. Theskinning system may include an article feeding mechanism configured toalign the article with the skinning pipe and push the article into theinner space of the skinning pipe, and a transfer system configured tohold the article and move the article out of the skinning pipe as thearticle moves axially along the inner space of the skinning pipe toreceive the flowable mixture.

According to a two hundred and eighty-seventh embodiment, the articlefeeding mechanism of the two hundred and eighty-sixth embodiment mayinclude a platen configured to support the article placed thereon, and acentering mechanism configured to center the article placed on theplaten.

According to a two hundred and eighty-eighth embodiment, centeringmechanism of the two hundred and eighty-seventh embodiment may include aplurality of centering devices each comprising a centering actuatorconfigured to center the article.

According to a two hundred and eighty-ninth embodiment, each centeringdevice of the two hundred and eighty-eighth embodiment may include anadjusting mechanism configured to adjust a position of the at least onecentering actuator relative to the platen.

According to a two hundred and ninetieth embodiment, the at least oneadjusting mechanism of the two hundred and eighty-ninth embodiment mayinclude a locating plate having a plurality of holes, and a locating pinconfigured to engage with one of the plurality of holes.

According to a two hundred and ninety-first embodiment, the adjustingmechanism of the two hundred and ninetieth embodiment may include asupport having at least one guide hole, a rod configured to slide withinthe at least one guide hole, and a bracket mounted to the support andhaving a hole configured to engage with the locating pin to secure aposition of the at least one centering actuator relative to the platen.

According to a two hundred and ninety-second embodiment, the centeringactuator of the two hundred and ninetieth embodiment may be mounted toat least one of the locating plate and the rod.

According to a two hundred and ninety-third embodiment, the at least oneadjusting mechanism of the two hundred and ninety-second embodiment mayinclude a motor configured to adjust the position of the at least onecentering actuator.

According to a two hundred and ninety-fourth embodiment, the centeringmechanism of any of the two hundred and eighty-seventh to two hundredand ninety-third embodiment may include at least one air knifeconfigured to blow air toward at least one of the unskinned article andthe platen.

According to a two hundred and ninety-fifth embodiment, the articlefeeding mechanism of any of the two hundred and eighty-seventh to twohundred and ninety-third embodiment may be mounted to a lower carriagemovable along a rail relative to the skinning pipe.

According to a two hundred and ninety-sixth embodiment, the articlefeeding mechanism and the lower carriage of the two hundred andninety-fifth embodiment may be disposed below the skinning pipe in avertical direction.

According to a two hundred and ninety-seventh embodiment, the articlefeeding mechanism of the two hundred and ninety-sixth embodiment may beconfigured to push the article into the skinning pipe from below theskinning pipe in the vertical direction.

According to a two hundred and ninety-eighth embodiment, in the skinningsystem of any of the two hundred and eighty-sixth to two hundred andninety-third embodiment, the article feeding mechanism may be mounted ona lower carriage, and the transfer system may be mounted on an uppercarriage. The lower carriage and the upper carriage may be mounted on avertical rail and move along the vertical rail, and the lower carriagemay be disposed below the skinning pipe. The upper carriage may bedisposed above the skinning pipe.

According to a two hundred and ninety-ninth embodiment, the articlefeeding mechanism of any of the two hundred and eighty-fifth to twohundred and ninety-third embodiment may include a flexure shaftconfigured to support the platen, the flexure shaft being deflectablewhile the article feeding mechanism pushes the article into the skinningpipe.

According to a three hundredth embodiment, the article feeding mechanismof the two hundred and ninety-ninth embodiment may include a tiltlimiter located adjacent the flexure shaft and configured to limitdeflection of the flexure shaft.

According to a three hundredth and first embodiment, the transfer systemof any of the two hundred and eighty-sixth to two hundred andninety-third embodiment may be mounted to an upper carriage movablealong a rail relative to the skinning pipe.

According to a three hundredth and second embodiment, the upper carriageand the transfer system of the three hundred and first embodiment may bedisposed above the skinning pipe in a vertical direction.

According to a three hundredth and third embodiment, the transfer systemof the three hundred and second embodiment may be configured to pull thearticle upward in the vertical direction out of the skinning pipe.

According to a three hundredth and fourth embodiment, the transfersystem of any of the two hundred and eighty-sixth to two hundred andninety-third embodiment may include a vacuum system configured togenerate a vacuum pressure within the article. The vacuum system mayinclude a vacuum chuck configured to hold the article using the vacuumpressure, and pull the article out of the skinning pipe while holdingthe article using the vacuum pressure.

According to a three hundredth and fifth embodiment, the vacuum chuck ofthe three hundredth and fourth embodiment may be a multi-zone vacuumchuck, each zone being independently controlled.

According to a three hundredth and fifth embodiment, the transfer systemof any of the two hundred and eighty-sixth to two hundred andninety-third embodiment may include a vacuum system configured togenerate multiple vacuum zones within more than one article. The vacuumsystem may be configured to hold the more than one article by a vacuumpressure and move the more than one article out of the skinning pipe.

According to a three hundred and seventh embodiment, the skinning systemof the three hundred and sixth embodiment may include a first spacerdisposed at a bottom surface of a first article to seal off a firstvacuum zone, and a second spacer disposed at a bottom surface of asecond article to seal off a second vacuum zone, a shape of the firstspacer being different from a shape of the second spacer.

According to a three hundred and eighth embodiment, the skinning systemof any of the two hundred and eighty-sixth to two hundred andninety-third embodiment may include at least one force sensor configuredto measure at least one force experienced by at least one of thetransfer system and the article feeding mechanism.

According to a three hundred and ninth embodiment, the skinning systemof the three hundred and eighth embodiment may include a control systemconfigured to control motions of the transfer system and the articlefeeding mechanism based on the at least one force.

According to a three hundred and tenth embodiment, the control system ofthe three hundred and ninth embodiment may be configured to adjust atleast one of a position and a speed of at least one of the articlefeeding mechanism and the transfer system based on the at least oneforce.

According to a three hundred and eleventh embodiment, the at least oneforce sensor of the three hundred and eighth embodiment may include atleast one first force sensor configured to measure a first forceexperienced by the transfer system or an upper carriage to which thetransfer system is mounted, and at least one second force sensorconfigured to measure a second force experienced by the article feedingmechanism or a lower carriage to which the article feeding mechanism ismounted.

According to a three hundred and twelfth embodiment, in the skinningsystem of the three hundred and ninth embodiment, the transfer systemmay include a vacuum system configured to generate multiple vacuumzones, and the control system may be configured to activate ordeactivate one or more of the multiple vacuum zones based on the atleast one force.

According to a three hundred and thirteenth embodiment, the skinningsystem of any of the two hundred and eighty-sixth to two hundred andninety-third embodiment may include at least one laser device disposedadjacent an inlet of the skinning pipe and configured to measure adimension of an unskinned article, the dimension including at least oneof a diameter, a radius, a circumference, and an outer peripherallength.

According to a three hundred and fourteenth embodiment, the at least onelaser device of the three hundred and thirteenth embodiment may includea plurality of laser devices, each laser devices including a laser unitand a camera.

According to a three hundred and fifteenth embodiment, the skinningsystem of any of the two hundred and eighty-sixth to two hundred andninety-third embodiment may include at least one laser device disposedadjacent an outlet of the skinning pipe and configured to monitorpresence of a defect on a skinned article coated with the flowablemixture.

According to a three hundred and sixteenth embodiment, in the skinningsystem of the three hundred and fifteenth embodiment, the at least onelaser device disposed adjacent the outlet of the skinning pipe is alsoconfigured to detect the defect based on monitoring the presence of thedefect.

According to a three hundred and seventeenth embodiment, the skinningsystem of any of the two hundred and eighty-sixth, two hundred andeighty-seventh, two hundred and eighty-eighth, two hundred andeighty-ninth, two hundred and ninetieth, two hundred and ninety-first,two hundred and ninety-second, or two hundred and ninety-thirdembodiments further comprises at least one laser device disposedadjacent an outlet of the skinning pipe and configured to measure adimension of a skinned article.

According to a three hundred and eighteenth embodiment, in the skinningsystem of the three hundred and seventeenth embodiment, the dimensioncomprises at least one of a diameter, a radius, a circumference, and anouter peripheral length.

According to a three hundred and nineteenth embodiment, the skinningsystem of any of the two hundred and eighty-sixth, two hundred andeighty-seventh, two hundred and eighty-eighth, two hundred andeighty-ninth, two hundred and ninetieth, two hundred and ninety-first,two hundred and ninety-second, or two hundred and ninety-thirdembodiments further comprises at least one first laser device disposedadjacent an inlet of the skinning pipe and configured to measure adimension of an unskinned article, the dimension including at least oneof a diameter, a radius, a circumference, and an outer peripherallength, and at least one second laser device disposed adjacent an outletof the skinning pipe and configured to measure a dimension of a skinnedarticle which is the unskinned article applied with the flowable mixtureat an outer surface, the dimension including at least one of a diameter,a radius, a circumference, and an outer peripheral length.

According to a three hundred and twentieth embodiment, the skinningsystem of any of the two hundred and eighty-sixth, two hundred andeighty-seventh, two hundred and eighty-eighth, two hundred andeighty-ninth, two hundred and ninetieth, two hundred and ninety-first,two hundred and ninety-second, or two hundred and ninety-thirdembodiments further comprises a controller configured to receive dataregarding a dimension of the unskinned article and data regarding adimension of the skinned article and calculate a thickness of theflowable mixture applied to the outer surface of the unskinned articlebased on the dimensions of the unskinned article and the skinnedarticle.

According to a three hundred and twenty-first embodiment, in theskinning system of the three hundred and twentieth embodiment, thedimension comprises at least one of a diameter, a radius, acircumference, and an outer peripheral length.

According to a three hundred and twenty-second embodiment, the skinningsystem of any of the two hundred and eighty-sixth, two hundred andeighty-seventh, two hundred and eighty-eighth, two hundred andeighty-ninth, two hundred and ninetieth, two hundred and ninety-first,two hundred and ninety-second, or two hundred and ninety-thirdembodiments further comprises a frame structure including a raildisposed in a vertical direction, and the manifold is mounted to amiddle portion of the frame structure, and the article feeding mechanismis mounted to a lower carriage, the lower carriage being mounted to therail below the manifold, and the transfer system is mounted to an uppercarriage, the upper carriage being mounted to the rail above themanifold.

According to a three hundred and twenty-third embodiment, in theskinning system of any of the two hundred and eighty-sixth, two hundredand eighty-seventh, two hundred and eighty-eighth, two hundred andeighty-ninth, two hundred and ninetieth, two hundred and ninety-first,two hundred and ninety-second, or two hundred and ninety-thirdembodiments, the manifold further comprises a pressure adjustment systemconfigured to adjust a pressure of the flowable mixture adjacent theskinning pipe.

According to a three hundred and twenty-fourth embodiment, in theskinning system of the three hundred and twenty-third embodiment, themanifold further comprises a ring mounted to a lower manifold piece ofthe manifold and configured to move along the skinning pipe under theactuation of the pressure adjustment system.

According to a three hundred and twenty-fifth embodiment, in theskinning system of any of the two hundred and eighty-sixth, two hundredand eighty-seventh, two hundred and eighty-eighth, two hundred andeighty-ninth, two hundred and ninetieth, two hundred and ninety-first,two hundred and ninety-second, or two hundred and ninety-thirdembodiments, the manifold further comprises a skin thickness sensormounted to a wall of the skinning pipe and configured to measure athickness of the flowable mixture on a skinned article.

According to a three hundred and twenty-sixth embodiment, in theskinning system of the three hundred and twenty-fifth embodiment, theskin thickness sensor comprises at least one conductor configured toapply a current to the flowable mixture on the skinned article and aprobe body housing the at least one conductor.

According to a three hundred and twenty-seventh embodiment, in theskinning system of any of the two hundred and eighty-sixth, two hundredand eighty-seventh, two hundred and eighty-eighth, two hundred andeighty-ninth, two hundred and ninetieth, two hundred and ninety-first,two hundred and ninety-second, or two hundred and ninety-thirdembodiments, the manifold comprises an upper manifold piece and a lowermanifold piece joined together with the upper manifold piece.

According to a three hundred and twenty-eighth embodiment, in theskinning system of the three hundred and twenty-seventh embodiment, themanifold comprises a locating pin located in at least one of the uppermanifold piece and the lower manifold piece and a locating cylinderlocated in at least one of the lower manifold piece and the uppermanifold piece, the locating cylinder and the locating pin engaging withone another to join the upper manifold piece and the lower manifoldpiece.

According to a three hundred and twenty-ninth embodiment, in theskinning system of any of the two hundred and eighty-sixth, two hundredand eighty-seventh, two hundred and eighty-eighth, two hundred andeighty-ninth, two hundred and ninetieth, two hundred and ninety-first,two hundred and ninety-second, or two hundred and ninety-thirdembodiments the manifold is mounted to a mounting bracket, the manifoldfurther comprising at least one locating pad for locating the manifoldon the mounting bracket.

According to a three hundred and thirtieth embodiment, in the skinningsystem of any of the two hundred and eighty-sixth, two hundred andeighty-seventh, two hundred and eighty-eighth, two hundred andeighty-ninth, two hundred and ninetieth, two hundred and ninety-first,two hundred and ninety-second, or two hundred and ninety-thirdembodiments, the manifold is mounted to a mounting bracket, the manifoldfurther comprising at least one locating blocks for locating themanifold on the mounting bracket.

According to a three hundred and thirty-first embodiment, in theskinning system of any of the two hundred and eighty-sixth, two hundredand eighty-seventh, two hundred and eighty-eighth, two hundred andeighty-ninth, two hundred and ninetieth, two hundred and ninety-first,two hundred and ninety-second, or two hundred and ninety-thirdembodiments, the skinning pipe includes a wall having a plurality ofholes and the grooves are configured to deliver the flowable mixturefrom the manifold to the inner space of the skinning pipe through theholes.

According to a three hundred and thirty-second embodiment, in theskinning system of the three hundred and thirty-first embodiment, theflowable mixture within the grooves is pressurized.

According to a three hundred and thirty-third embodiment, in theskinning system of the three hundred and thirty-second embodiment, theplurality of grooves are configured to deliver the flowable mixture to acircumference of the wall of the skinning pipe.

According to a three hundred and thirty-fourth embodiment, the skinningsystem of any of the two hundred and eighty-sixth, two hundred andeighty-seventh, two hundred and eighty-eighth, two hundred andeighty-ninth, two hundred and ninetieth, two hundred and ninety-first,two hundred and ninety-second, or two hundred and ninety-thirdembodiments further comprises at least one robot configured to load orunload the article.

According to a three hundred and thirty-fifth embodiment, in theskinning system of the three hundred and thirty-fourth embodiment, theat least one robot comprises a loading robot and an unloading robot, theloading robot comprises a vacuum chuck configured to hold and lift anunskinned article using a vacuum pressure, and the unloading robotcomprises at least one adjustable arm configured to receive a skinnedarticle.

According to a three hundred and thirty-sixth embodiment, in theskinning system of the three hundred and thirty-fifth embodiment, theunloading robot further comprises a sensor configured to detect thepresence of the skinned article on the at least one adjustable arm.

According to a three hundred and thirty-seventh embodiment, the presentdisclosure relates to a manifold assembly for a skinning system thatapplies a flowable mixture to an article. The manifold assembly mayinclude a manifold including a plurality of grooves configured todeliver the flowable mixture, a skinning pipe configured to receive theflowable mixture from the grooves of the manifold and apply the flowablemixture to an outer surface of the article, and a skin thickness sensormounted to the skinning pipe and configured to apply an electriccurrent, using a circuit, to a portion of the flowable mixture appliedto the outer surface of the article. The skin thickness sensor may alsobe configured to measure a voltage across a portion of the circuit, anddetermine a thickness of the flowable mixture applied to the outersurface of the article based on the measured voltage and a predeterminedrelationship between thicknesses and voltages.

According to a three hundred and thirty-eighth embodiment, the manifoldassembly of the three hundred and thirty-seventh embodiment furthercomprises a pressure adjustment system configured to adjust a pressureof the flowable mixture adjacent the skinning pipe.

According to a three hundred and thirty-ninth embodiment, the manifoldassembly of the three hundred and thirty-eighth embodiment furthercomprises a ring mounted to a lower manifold piece of the manifold andconfigured to move along the skinning pipe under actuation of thepressure adjustment system.

According to a three hundred and fortieth embodiment, in the manifoldassembly of the three hundred and thirty-seventh, three hundred andthirty-eighth, or three hundred and thirty-ninth embodiments, the skinthickness sensor comprises at least one conductor configured to applythe electric current to the flowable mixture applied to the outersurface of the article and a probe body housing the at least oneconductor.

According to a three hundred and forty-first embodiment, in the manifoldassembly of the three hundred and thirty-seventh, three hundred andthirty-eighth, or three hundred and thirty-ninth embodiments, themanifold comprises an upper manifold piece and a lower manifold piecejoined together with the upper manifold piece.

According to a three hundred and forty-second embodiment, in themanifold assembly of the three hundred and forty-first embodiment, themanifold comprises a locating pin located in at least one of the uppermanifold piece and the lower manifold piece and a locating cylinderlocated in at least one of the lower manifold piece and the uppermanifold piece, the locating cylinder and the locating pin engaging withone another to join the upper manifold piece and the lower manifoldpiece.

According to a three hundred and forty-third embodiment, in the manifoldassembly of the three hundred and thirty-seventh, three hundred andthirty-eighth, or three hundred and thirty-ninth embodiments, themanifold is mounted to a mounting bracket, the manifold furthercomprising at least one locating pad for locating the manifold on themounting bracket.

According to a three hundred and forty-fourth embodiment, in themanifold assembly of the three hundred and thirty-seventh, three hundredand thirty-eighth, or three hundred and thirty-ninth embodiments, themanifold is mounted to a mounting bracket, the manifold furthercomprising at least one locating block for locating the manifold on themounting bracket.

According to a three hundred and forty-fifth embodiment, in the manifoldassembly of the three hundred and thirty-seventh, three hundred andthirty-eighth, or three hundred and thirty-ninth embodiments, theskinning pipe includes a wall having a plurality of holes and thegrooves are configured to deliver the flowable mixture from the manifoldto an inner space of the skinning pipe through the holes.

According to a three hundred and forty-sixth embodiment, in the manifoldassembly of the three hundred and forty-fifth embodiment the flowablemixture within the grooves is pressurized.

According to a three hundred and forty-seventh embodiment, in themanifold assembly of the three hundred and forty-fifth embodiment theplurality of grooves are configured to deliver the flowable mixture to acircumference of the wall of the skinning pipe.

According to a three hundred and forty-eighth embodiment, in themanifold assembly of the three hundred and thirty-seventh, three hundredand thirty-eighth, or three hundred and thirty-ninth embodiments, theskinning pipe is mounted to the manifold.

According to a three hundred and forty-ninth embodiment, the presentdisclosure relates to a manifold assembly for a skinning system thatapplies a flowable mixture to an article. The manifold assembly mayinclude a manifold including a plurality of grooves configured todeliver the flowable mixture, a skinning pipe configured to receive theflowable mixture from the grooves of the manifold and apply the flowablemixture to an outer surface of the article, and a pressure adjustmentsystem configured to adjust a pressure of the flowable mixture adjacentthe skinning pipe.

According to a three hundred and fiftieth embodiment, the manifoldassembly of the three hundred and forty-ninth embodiment furthercomprises a ring mounted to a lower manifold piece of the manifold andconfigured to move along the skinning pipe under actuation of thepressure adjustment system.

According to a three hundred and fifty-first embodiment, the manifoldassembly of the three hundred and forty-ninth or three hundred andfiftieth embodiments further comprises a skin thickness sensorcomprising at least one conductor configured to apply an electriccurrent to the flowable mixture applied to the outer surface of thearticle and a probe body housing the at least one conductor.

According to a three hundred and fifty-second embodiment, in themanifold assembly of the three hundred and forty-ninth or three hundredand fiftieth embodiments, the skin thickness sensor further comprises(i) a circuit comprising a power source configured to supply theelectric current and a circuit portion across which a voltage ismeasured, and (ii) a controller configured to determine a thickness ofthe flowable mixture applied to the outer surface of the article basedon the measured voltage and a predetermined relationship betweenthicknesses and voltages.

According to a three hundred and fifty-third embodiment, in the manifoldassembly of the three hundred and forty-ninth or three hundred andfiftieth embodiments, the manifold comprises an upper manifold piece anda lower manifold piece joined together with the upper manifold piece.

According to a three hundred and fifty-fourth embodiment, in themanifold assembly of the three hundred and fifty-third embodiment, themanifold comprises a locating pin located in at least one of the uppermanifold piece and the lower manifold piece, and a locating cylinderlocated in at least one of the lower manifold piece and the uppermanifold piece, the locating cylinder and the locating pin engaging withone another to join the upper manifold piece and the lower manifoldpiece.

According to a three hundred and fifty-fifth embodiment, in the manifoldassembly of the three hundred and forty-ninth or three hundred andfiftieth embodiments, the manifold is mounted to a mounting bracket, andthe manifold further comprises at least one locating pad for locatingthe manifold on the mounting bracket.

According to a three hundred and fifty-sixth embodiment, in the manifoldassembly of the three hundred and forty-ninth or three hundred andfiftieth embodiments, the manifold is mounted to a mounting bracket, andthe manifold further comprises at least one locating blocks for locatingthe manifold on the mounting bracket.

According to a three hundred and fifty-seventh embodiment, in themanifold assembly of the three hundred and forty-ninth or three hundredand fiftieth embodiments, the skinning pipe includes a wall having aplurality of holes and the grooves are configured to deliver theflowable mixture from the manifold to an inner space of the skinningpipe through the holes.

According to a three hundred and fifty-eighth embodiment, in themanifold assembly of the three hundred and forty-ninth or three hundredand fiftieth embodiments, the flowable mixture within the grooves ispressurized.

According to a three hundred and fifty-ninth embodiment, in the manifoldassembly of the three hundred and fifty-seventh embodiment, theplurality of grooves are configured to deliver the flowable mixture to acircumference of the wall of the skinning pipe.

According to a three hundred and sixtieth embodiment, in the manifoldassembly of the three hundred and forty-ninth or three hundred andfiftieth embodiments, the skinning pipe is mounted to the manifold.

According to a three hundred and sixty-first embodiment, the presentdisclosure relates to a flexure shaft assembly for a skinning system.The flexure shaft assembly may include a flexure shaft configured tosupport a platen configured to support an article, and at least one tiltlimiter configured to limit an amount of deflection of the flexureshaft. As the article is pushed into an inner space of a skinning pipeto receive a flowable mixture, the flexure shaft may deflect in adirection substantially perpendicular to an axis of the skinning pipe tocompensate for misalignment between the article and the skinning pipe.The at least one tilt limiter may be configured to limit the deflectionof the flexure shaft.

According to a three hundred and sixty-second embodiment, in the flexureshaft assembly of the three hundred and sixty-first embodiment, the tiltlimiter comprises a radial stop configured to limit a radial deflectionof the flexure shaft and an axial stop configured to limit an axialdeflection of the flexure shaft.

According to a three hundred and sixty-third embodiment, the presentdisclosure relates to an article feeding mechanism for a skinningsystem. The article feeding mechanism may include a platen configured tosupport an unskinned article, and a centering mechanism configured toalign the unskinned article with a skinning pipe. The centeringmechanism may include a plurality of centering devices disposed aroundthe platen, each centering device including a centering actuator and anadjusting mechanism configured to adjust a position of the centeringactuator based on a dimension of the unskinned article, the dimensionincluding at least one of a diameter, a radius, a circumference, and anouter peripheral length.

According to a three hundred and sixty-fourth embodiment, in the articlefeeding mechanism of the three hundred and sixty-third embodiment, theadjusting mechanism comprises a locating plate having a plurality ofholes and a locating pin configured to engage with one of the pluralityof holes.

According to a three hundred and sixty-fifth embodiment, in the articlefeeding mechanism of the three hundred and sixty-fourth embodiment, theadjusting mechanism comprises a support having at least one guide hole,a rod configured to slide within the at least one guide hole, and abracket mounted to the support and having a hole configured to engagewith the locating pin to secure a position of the at least one centeringactuator relative to the platen.

According to a three hundred and sixty-sixth embodiment, in the articlefeeding mechanism of the three hundred and sixty-fifth embodiment, thecentering actuator is mounted to at least one of the locating plate andthe rod.

According to a three hundred and sixty-seventh embodiment, in thearticle feeding mechanisms of any of the three hundred and sixty-third,three hundred and sixty-fourth, three hundred and sixty-fifth, or threehundred and sixty-sixth embodiments the adjusting mechanism comprises amotor configured to adjust the position of the centering device.

According to a three hundred and sixty-eighth embodiment, in the articlefeeding mechanisms of any of the three hundred and sixty-third, threehundred and sixty-fourth, three hundred and sixty-fifth, or threehundred and sixty-sixth embodiments the centering mechanism comprises atleast one air knife configured to blow air toward at least one of theunskinned article and the platen.

According to a three hundred and sixty-ninth embodiment, the articlefeeding mechanisms of any of the three hundred and sixty-third, threehundred and sixty-fourth, three hundred and sixty-fifth, or threehundred and sixty-sixth embodiments may further comprise a flexure shaftconfigured to support the platen, the flexure shaft being deflectable tocompensate for misalignment between the unskinned article and theskinning pipe as the unskinned article is pushed into an inner space ofthe skinning pipe.

According to a three hundred and seventieth embodiment, the articlefeeding mechanisms of any of the three hundred and sixty-fourth, threehundred and sixty-fifth, or three hundred and sixty-sixth embodimentsmay further comprise a tilt limiter located adjacent the flexure shaftand configured to limit deflection of the flexure shaft.

According to a three hundred and seventy-first embodiment, in thearticle feeding mechanism of the three hundred and seventiethembodiment, the tilt limiter comprises a radial stop configured to limita radial deflection of the flexure shaft and an axial stop configured tolimit an axial deflection of the flexure shaft.

According to a three hundred and seventy-second embodiment, the presentdisclosure relates to a multi-zone vacuum system. The multi-zone vacuumsystem may include two or more vacuum ports, a vacuum chuck includingtwo or more vacuum channels fluidly connected to the two or more vacuumports, and a chuck mount disposed between the two or more vacuum portsand the vacuum chuck, the vacuum chuck being mounted on one side of thechuck mount, and the two or more vacuum ports being mounted on anotherside of the chuck mount. Each of the two or more vacuum ports may beindependently controlled to provide vacuum pressure to the two or morevacuum channels.

According to a three hundred and seventy-third embodiment, themulti-zone vacuum system of the three hundred and seventy-secondembodiment is configured to hold the more than one article using themultiple vacuum zones, a first spacer being disposed at a bottom surfaceof a first article to seal off a first vacuum zone, and a second spacerbeing disposed at a bottom surface of a second article to seal off asecond vacuum zone, a shape of the first spacer being different from ashape of the second spacer.

According to a three hundred and seventy-fourth embodiment, the presentdisclosure relates to a skinning system for applying a flowable mixtureto an article. The skinning system may include a skinning pipeconfigured to receive the article and apply the flowable mixture to thearticle as the article moves axially through the skinning pipe, amanifold including a plurality of grooves configured to deliver theflowable mixture to the skinning pipe, and a skinning control system.The skinning control system may include a feed forward controllerconfigured to determine an adjustment to at least one of a deliverypressure set point, a return pressure set point, a speed of a pump, adelivery valve position, a flow rate set point, a skinning speed, and apressure relief system position, based on a variation relating to atleast one of a flow rate of the flowable mixture, a viscosity of theflowable mixture, or dimensions of incoming unskinned articles, thedimensions including at least one of a diameter, a radius, acircumference, and an outer peripheral length. The skinning controlsystem may include at least one feedback controller configured todetermine at least one of a skinning pipe pressure set point, thedelivery pressure set point, the return pressure set point, the speed ofthe pump, the delivery valve position, and the flow rate set point,based on a result of monitoring presence of a defect on a skinnedarticle coated with the flowable mixture. The skinning control systemmay include a communication unit configured to transmit a control signalto at least one of a mixture delivery system and the skinning systembased on an output from at least one of the feed forward controller andthe feedback controller.

According to a three hundred and seventy-fifth embodiment, the presentdisclosure relates to a skinning system for applying a flowable mixtureto an article. The skinning system may include a skinning pipeconfigured to receive the article and apply the flowable mixture to thearticle as the article moves axially through the skinning pipe, amanifold including a plurality of grooves configured to deliver theflowable mixture to the skinning pipe, and a skinning control system.The skinning control system may include a feed forward controllerconfigured to determine an adjustment to at least one of a deliverypressure set point, a return pressure set point, a speed of a pump, adelivery valve position, a flow rate set point, a skinning speed, and apressure relief system position, based on a variation relating to atleast one of a flow rate of the flowable mixture, a viscosity of theflowable mixture, or dimensions of incoming unskinned articles.

According to a three hundred and seventy-sixth embodiment, in theskinning system of the three hundred and seventy-fifth embodiment, thedimensions comprise at least one of a diameter, a radius, acircumference, and an outer peripheral length.

According to a three hundred and seventy-seventh embodiment, theskinning system of the three hundred and seventy-sixth embodimentfurther comprises at least one feedback controller configured todetermine at least one of a skinning pipe pressure set point, thedelivery pressure set point, the return pressure set point, the speed ofthe pump, the delivery valve position, and the flow rate set point,based on a result of monitoring presence of a defect on a skinnedarticle coated with the flowable mixture.

According to a three hundred and seventy-eighth embodiment, the skinningsystem of the three hundred and seventy-seventh embodiment furthercomprises a communication unit configured to transmit a control signalto at least one of a mixture delivery system and the skinning systembased on an output from at least one of the feed forward controller andthe feedback controller.

According to a three hundred and seventy-ninth embodiment, in theskinning system of the three hundred and seventy-eighth embodiment, thecommunication unit is configured to receive real-time or near real-timemeasurements of at least one of a skinning pipe pressure, a deliverypressure, a return pressure, the speed of the pump, the delivery valveposition, the flow rate, the viscosity, the dimensions of the incomingunskinned articles, the skinning speed, or the pressure relief systemposition.

According to a three hundred and eightieth embodiment, in the skinningsystem of any of the three hundred and seventy-seventh, three hundredand seventy-eighth, or three hundred and seventy-ninth embodiments, theat least one feedback controller comprises a first feedback controllerconfigured to determine the speed of the pump based on a measured returnpressure or delivery pressure.

According to a three hundred and eighty-first embodiment, in theskinning system of the three hundred and eightieth embodiment, the atleast one feedback controller comprises a second feedback controllerconfigured to determine at least one of the return pressure set pointand the delivery pressure set point based on a measured skinning pipepressure, and the first feedback controller is configured to determinethe speed of the pump also based on at least one of the return pressureset point and the delivery pressure set point.

According to a three hundred and eighty-second embodiment, in theskinning system of the three hundred and eighty-first embodiment,monitoring the presence of the defect comprises detecting a type of thedefect, and the at least one feedback controller comprises a thirdfeedback controller configured to determine the skinning pipe pressureset point based on the type of defect, and the second feedbackcontroller is configured to determine at least one of the returnpressure set point and the delivery pressure set point also based onskinning pipe pressure set point.

According to a three hundred and eighty-third embodiment, in theskinning system of any of the three hundred and seventy-seventh, threehundred and seventy-eighth, or three hundred and seventy-ninthembodiments, the at least one feedback controller comprises a firstfeedback controller configured to determine at least one of the speed ofthe pump and the delivery valve position based on a measured skinningpipe pressure.

According to a three hundred and eighty-fourth embodiment, in theskinning system of the three hundred and eighty-third embodiment,monitoring the presence of the defect comprises detecting a type of thedefect, and the at least one feedback controller comprises a secondfeedback controller configured to determine the skinning pipe pressureset point based on the type of defect, and the first feedback controllerconfigured to determine at least one of the speed of the pump and thedelivery valve position also based on the skinning pipe pressure setpoint.

According to a three hundred and eighty-fifth embodiment, in theskinning system of any of the three hundred and seventy-seventh, threehundred and seventy-eighth, or three hundred and seventy-ninthembodiments, the at least one feedback controller comprises a firstfeedback controller configured to determine the speed of the pump basedon a measured flow rate of the flowable mixture in the mixture deliverysystem.

According to a three hundred and eighty-sixth embodiment, in theskinning system of the three hundred and eighty-fifth embodiment, the atleast one feedback controller comprises a second feedback controllerconfigured to determine the flow rate set point based on a skinning pipepressure measured in the skinning system, and the first feedbackcontroller is configured to determine the speed of the pump also basedon the flow rate set point.

According to a three hundred and eighty-seventh embodiment, in theskinning system of the three hundred and eighty-sixth embodiment,monitoring the presence of the defect comprises detecting a type of thedefect, and the at least one feedback controller comprises a thirdfeedback controller configured to determine the skinning pipe pressureset point based on the type of defect, and the second feedbackcontroller is configured to determine the flow rate set point also basedon the skinning pipe pressure set point.

According to a three hundred and eighty-eighth embodiment, in theskinning system of any of the three hundred and seventy-fifth, threehundred and seventy-sixth, three hundred and seventy-seventh, threehundred and seventy-eighth, or three hundred and seventy-ninthembodiments, the feed forward controller comprises a second feed forwardcontroller configured to determine an adjustment to at least one of thereturn pressure set point and the delivery pressure set point based onthe variation relating to at least one of the measured viscosity andmeasured flow rate.

According to a three hundred and eighty-ninth embodiment, in theskinning system of any of the three hundred and seventy-fifth, threehundred and seventy-sixth, three hundred and seventy-seventh, threehundred and seventy-eighth, or three hundred and seventy-ninthembodiments, the feed forward controller comprises a second feed forwardcontroller configured to determine an adjustment to at least one of thespeed of the pump and the delivery valve position based on the variationrelating to at least one of the measured viscosity and the measured flowrate.

According to a three hundred and ninetieth embodiment, in the skinningsystem of any of the three hundred and seventy-fifth, three hundred andseventy-sixth, three hundred and seventy-seventh, three hundred andseventy-eighth, or three hundred and seventy-ninth embodiments, the feedforward controller comprises a second feed forward controller configuredto determine an adjustment to the flow rate set point based on thevariation relating to at least one of the measured viscosity and themeasured flow rate.

According to a three hundred and ninety-first embodiment, in theskinning system of any of the three hundred and seventy-sixth, threehundred and seventy-seventh, three hundred and seventy-eighth, or threehundred and seventy-ninth embodiments, the feed forward controllercomprises a second feed forward controller configured to determine anadjustment to the skinning speed based on the variation relating to thedimensions of incoming unskinned articles measured in the skinningsystem.

According to a three hundred and ninety-second embodiment, in theskinning system of any of the three hundred and seventy-sixth, threehundred and seventy-seventh, three hundred and seventy-eighth, or threehundred and seventy-ninth embodiments, the feed forward controllercomprises a second feed forward controller configured to determine anadjustment to the pressure relief system position based on the variationrelating to the dimensions of incoming unskinned articles measured inthe skinning system.

According to a three hundred and ninety-third embodiment, in theskinning system of any of the three hundred and seventy-seventh, threehundred and seventy-eighth, or three hundred and seventy-ninthembodiments, the at least one feedback controller comprises a firstfeedback controller configured to determine the skinning speed based ona measured skinning pipe pressure.

According to a three hundred and ninety-fourth embodiment, in theskinning system of any of the three hundred and seventy-seventh, threehundred and seventy-eighth, or three hundred and seventy-ninthembodiments, the at least one feedback controller comprises a firstfeedback controller configured to determine the pressure relief systemposition based on a measured skinning pipe pressure.

According to a three hundred and ninety-fifth embodiment, the skinningsystem of any of the three hundred and seventy-sixth, three hundred andseventy-seventh, three hundred and seventy-eighth, or three hundred andseventy-ninth embodiments is configured to switch between a firstskinning pipe pressure control scheme and a second skinning pipe controlscheme based on the dimensions of incoming unskinned articles measuredin the skinning system.

According to a three hundred and ninety-sixth embodiment, the presentdisclosure relates to a method of operating a skinning system forapplying a flowable mixture to an article. The method may includealigning the article with a skinning pipe, pushing the article into aninner space of the skinning pipe, and delivering the flowable mixture tothe skinning pipe. The method may include applying the flowable mixtureto the article while the article moves along the inner space of theskinning pipe, and holding and moving the article out of the skinningpipe as the article moves along the inner space of the skinning pipe toreceive the flowable mixture.

According to a three hundred and ninety-seventh embodiment, the methodof the three hundred and ninety-sixth embodiment further comprisesplacing the article on a platen, and aligning the article comprisescentering the article to align the article with the skinning pipe usinga plurality of centering devices disposed around the platen.

According to a three hundred and ninety-eighth embodiment, the method ofthe three hundred and ninety-seventh embodiment further comprisesadjusting positions of the centering devices based on a dimension of thearticle placed on the platen, the dimension including at least one of adiameter, a radius, a circumference, and an outer peripheral length.

According to a three hundred and ninety-ninth embodiment, the methods ofany of the three hundred and ninety-seventh or three hundred andninety-eighth embodiments further comprise blowing air toward at leastone of the platen and the article placed on the platen to blow offdebris.

According to a four hundredth embodiment, in the methods of any of thethree hundred and ninety-sixth, three hundred and ninety-seventh, orthree hundred and ninety-eighth embodiments, pushing the article intothe inner space of the skinning pipe comprises pushing the articleupward in a vertical direction from below an inlet of the skinning pipe.

According to a four hundred and first embodiment, the methods of any ofthe three hundred and ninety-sixth, three hundred and ninety-seventh, orthree hundred and ninety-eighth embodiments further comprise generatinga vacuum pressure within the article using a vacuum system.

According to a four hundred and second embodiment, the methods of any ofthe three hundred and ninety-sixth, three hundred and ninety-seventh, orthree hundred and ninety-eighth embodiments further comprise generatingmore than one vacuum zone within more than one article.

According to a four hundred and third embodiment, in the method of thefour hundred and first embodiment, holding and moving the articlecomprises holding and moving the article out of the skinning pipe usingthe vacuum pressure generated by the vacuum system.

According to a four hundred and fourth embodiment, in the method of thefour hundred and third embodiment, holding and moving the articlecomprises holding and pulling the article upward out of the skinningpipe.

According to a four hundred and fifth embodiment, in the methods of anyof the three hundred and ninety-sixth, three hundred and ninety-seventh,or three hundred and ninety-eighth embodiments, pushing the articlecomprises pushing the article using an article feeding mechanism andholding and moving the article out of the skinning pipe comprisesholding and moving the article using a transfer system, and the methodfurther comprises measuring at least one force experienced by at leastone of the transfer system and the article feeding mechanism andcontrolling motions of the at least one of the transfer system and thearticle feeding mechanism based on the at least one force.

According to a four hundred and sixth embodiment, in the method of thefour hundred and fifth embodiment, controlling motions of the at leastone of the transfer system and the article feeding mechanism comprisesadjusting at least one of a position and a speed of the at least one ofthe transfer system and the article feeding mechanism based on the atleast one force.

According to a four hundred and seventh embodiment, the methods ofeither the four hundred and fifth or four hundred and sixth embodimentsfurther comprise generating multiple vacuum zones, and whereincontrolling motions of the at least one of the transfer system and thearticle feeding mechanism comprises activating or deactivating one ormore of the multiple vacuum zones based on the at least one force.

According to a four hundred and eighth embodiment, the methods of any ofthe three hundred and ninety-sixth, three hundred and ninety-seventh, orthree hundred and ninety-eighth embodiments further comprise measuring adimension of at least one of an unskinned article and a skinned article.

According to a four hundred and ninth embodiment, in the method of thefour hundred and eighth embodiment, the dimension comprises at least oneof a diameter, a radius, a circumference, and an outer peripherallength.

According to a four hundred and tenth embodiment, the methods of any ofthe three hundred and ninety-sixth, three hundred and ninety-seventh, orthree hundred and ninety-eighth embodiments further comprise measuring adimension of an unskinned article, measuring a dimension of a skinnedarticle which is the unskinned article coated with the flowable mixture,and determining a thickness of the flowable mixture on the skinnedarticle based on the measured dimension of the unskinned article and thedimension of the skinned article.

According to a four hundred and eleventh embodiment, in the method ofthe four hundred and tenth embodiment, the dimension comprises at leastone of a diameter, a radius, a circumference, and an outer peripherallength.

According to a four hundred and twelfth embodiment, the methods of anyof the three hundred and ninety-sixth, three hundred and ninety-seventh,or three hundred and ninety-eighth embodiments further comprisemonitoring presence of a defect on a skinned article coated with theflowable mixture.

According to a four hundred and thirteenth embodiment, in the method ofthe four hundred and twelfth embodiment, monitoring the presence of thedefect comprises detecting a type of the defect.

According to a four hundred and fourteenth embodiment, the methods ofany of the three hundred and ninety-sixth, three hundred andninety-seventh, or three hundred and ninety-eighth embodiments furthercomprise moving a transfer system configured to hold and move thearticle out of the skinning pipe along a rail in a vertical directionabove the skinned pipe and moving an article feeding mechanismconfigured to push the article into the skinner pipe along the rail inthe vertical direction below the skinning pipe.

According to a four hundred and fifteenth embodiment, the methods of anyof the three hundred and ninety-sixth, three hundred and ninety-seventh,or three hundred and ninety-eighth embodiments further compriseadjusting a pressure of the flowable mixture adjacent the skinning pipeusing a pressure adjustment system.

According to a four hundred and sixteenth embodiment, in the method ofthe four hundred and fifteenth embodiment, adjusting the pressure of theflowable mixture adjacent the skinning pipe using the pressureadjustment system comprises moving a ring along the skinning pipe toadjust a space adjacent the skinning pipe available for the flowablemixture to flow.

According to a four hundred and seventeenth embodiment, the methods ofany of the three hundred and ninety-sixth, three hundred andninety-seventh, or three hundred and ninety-eighth embodiments furthercomprise measuring a thickness of the flowable mixture of a skinnedarticle using a skin thickness sensor.

According to a four hundred and eighteenth embodiment, in the fourhundred and seventeenth embodiment, measuring a thickness comprisesapplying an electric current to the flowable mixture using a circuit,measuring a voltage across a portion of the circuit, and determining thethickness based on the measured voltage and a predetermined relationshipbetween voltages and thicknesses.

According to a four hundred and nineteenth embodiment, the methods ofany of the three hundred and ninety-sixth, three hundred andninety-seventh, or three hundred and ninety-eighth embodiments furthercomprise loading an unskinned article onto a platen using a robot havinga vacuum chuck configured to generate a vacuum pressure within theunskinned article.

According to a four hundred and twentieth embodiment, the methods of anyof the three hundred and ninety-sixth, three hundred and ninety-seventh,or three hundred and ninety-eighth embodiments further compriseunloading a skinned article using a robot having an adjustable arm.

According to a four hundred and twenty-first embodiment, the methods ofany of the three hundred and ninety-sixth, three hundred andninety-seventh, or three hundred and ninety-eighth embodiments furthercomprise generating multiple vacuum zones and holding and moving morethan one article using the multiple vacuum zones.

According to a four hundred and twenty-second embodiment, the method ofthe four hundred and twenty-first embodiment further comprises usingspacers disposed at bottom surfaces of the more than one article to sealoff the multiple vacuum zones, the spacers being alternately disposed atthe bottom surfaces of the more than one article, at least two of thespacers having different shapes.

According to a four hundred and twenty-third embodiment, the presentdisclosure relates to a method of controlling a skinning process thatapplies a flowable mixture to an article. The method may includemeasuring, using at least one laser device, a variation relating to adimension of one or more incoming unskinned articles, determining, usinga feed forward controller, an adjustment to a skinning speed or apressure relief system position based on the measured variation, andtransmitting a control signal to a skinning system to adjust at leastone of the skinning speed and the pressure relief system position, basedon an output from the feed forward controller.

According to a four hundred and twenty-fourth embodiment, in the methodof the four hundred and twenty-third embodiment, the dimensions compriseat least one of a diameter, a radius, a circumference, and an outerperipheral length.

According to a four hundred and twenty-fifth embodiment, the presentdisclosure relates to a method of controlling a skinning pipe pressureassociated with a skinning pipe that applies a flowable mixture to anarticle. The method may include measuring a first dimension of a firstarticle prior to entering the skinning pipe, and determining that themeasured first dimension is outside of a predetermined limit. The methodmay include based on the determination that the measured first dimensionis outside of the predetermined limit, switching from a first controlscheme to a second control scheme, the first control scheme configuredfor controlling the skinning pipe pressure based on a viscosity or aflow rate, and the second control scheme configured for controlling theskinning pipe pressure based on variations in dimensions of incomingunskinned articles. The method may include measuring dimensions of apredetermined number of subsequent articles following the first article,and determining that the dimensions of the predetermined number ofsubsequent articles are within the predetermined limit. The method mayinclude based on the determination that the dimensions of thepredetermined number of subsequent articles are within the predeterminedlimit, switching from the second control scheme to the first controlscheme.

According to a four hundred and twenty-sixth embodiment, in the methodof the four hundred and twenty-fifth embodiment, the dimensions compriseat least one of a diameter, a radius, a circumference, and an outerperipheral length.

According to a four hundred and twenty-seventh embodiment, the presentdisclosure relates to a method for measuring a thickness of a flowablemixture coated on an outer surface of an article. The method may includeapplying an electric current, using a circuit, to a portion of theflowable mixture coated onto the outer surface of the article, measuringa voltage across a portion of the circuit, and determining, using acontroller, the thickness of the flowable mixture coated on the articlebased on the measured voltage and a predetermined relationship betweenthicknesses and voltages.

According to a four hundred and twenty-eighth embodiment, the presentdisclosure relates to a method of controlling a continuous axialskinning process. The method may include circulating a flowable mixturewithin a recirculation line, measuring at least one of a return pressureand a delivery pressure associated with the flowable mixture, anddetermining whether the at least one of the return pressure and thedelivery pressure is within a predetermined range compared to at leastone of a return pressure set point and a delivery pressure set point.The method may also include based on a determination that at least oneof the return pressure and the delivery pressure is within thepredetermined range, directing the flowable mixture to a delivery lineleading to a skinning system that applies the flowable mixture to anarticle.

According to a four hundred and twenty-ninth embodiment, the method ofthe four hundred and twenty-eighth embodiment further comprisesdetermining whether a skinning pipe pressure reaches a start-up pressureand, based on a determination that the skinning pipe pressure reachesthe start-up pressure, starting the skinning process using the skinningsystem to apply the flowable mixture to the article.

According to a four hundred and thirtieth embodiment, the presentdisclosure relates to a method of controlling a start-up of a skinningprocess that applies a flowable mixture to an article. The method mayinclude determining whether a target skinning speed is greater than apredetermined skinning speed, and based on a determination that thetarget skinning speed is less than the predetermined skinning speed,activating a pressure boost system mounted adjacent a skinning pipe toreduce a space adjacent the skinning pipe available for the flowablemixture to flow. The method may include based on a determination thatthe target skinning speed is greater than the predetermined skinningspeed, deactivating the pressure boost system to increase the spaceadjacent the skinning pipe available for the flowable mixture to flow.

According to a four hundred and thirty-first embodiment, the method ofthe four hundred and thirtieth embodiment further comprises starting theskinning process after activating the pressure boost system anddeactivating the pressure boost system to increase the space adjacentthe skinning pipe available for the flowable mixture to flow after theskinning pipe pressure increases to the predetermined threshold skinningpipe pressure.

According to a four hundred and thirty-second embodiment, the methods ofthe four hundred and thirtieth or four hundred and thirty-firstembodiments further comprise starting the skinning process afterdeactivating the pressure boost system and activating the pressure boostsystem to reduce the space adjacent the skinning pipe available for theflowable mixture to flow after the skinning pipe pressure decreases tothe predetermined threshold skinning pipe pressure.

According to a four hundred and thirty-third embodiment, the presentdisclosure relates to a method of controlling a start-up of a skinningsystem that applies a flowable mixture to an article. The method mayinclude determining that a target skinning speed is greater than apredetermined skinning speed, and starting the skinning process byincreasing a skinning speed incrementally in a plurality of steps untilthe target skinning speed is reached.

According to a four hundred and thirty-fourth embodiment, the presentdisclosure relates to a method of controlling a skinning system thatapplies a flowable mixture to an article. The method may includepushing, using an article feeding mechanism, the article into an innerspace of a skinning pipe, applying, using the skinning pipe, theflowable mixture received from a mixture delivery system to the articleas the article moves axially along the inner space of the skinning pipe,and measuring at least one of a flow rate of the flowable mixture, aviscosity of the flowable mixture, or dimensions of incoming unskinnedarticles. The method may include determining, using a feed forwardcontroller, an adjustment to at least one of a delivery pressure setpoint, a return pressure set point, a speed of a pump, a delivery valveposition, a flow rate set point, a skinning speed, and a pressure reliefsystem position, based on a variation in at least one of the measuredflow rate, viscosity, or dimensions of the incoming unskinned articles.The method may also include monitoring presence of a defect on a skinnedarticle coated with the flowable mixture, and determining, using afeedback controller, at least one of a skinning pipe pressure set point,the delivery pressure set point, the return pressure set point, thespeed of the pump, the delivery valve position, and the flow rate setpoint, based on a result of monitoring the presence of the defect on theskinned article. The method may also include transmitting a controlsignal to at least one of the mixture delivery system and the skinningsystem based on an output from at least one of the feed forwardcontroller and the feedback controller.

According to a four hundred and thirty-fifth embodiment, in the methodof the four hundred and thirty-fourth embodiment, monitoring thepresence of the defect comprises detecting a type of the defect, andwherein determining, using the feedback controller, at least one of theskinning pipe pressure set point, the delivery pressure set point, thereturn pressure set point, the speed of the pump, the delivery valveposition, and the flow rate set point, based on the result of monitoringthe presence of the defect comprises determining, using the feedbackcontroller, at least one of the skinning pipe pressure set point, thedelivery pressure set point, the return pressure set point, the speed ofthe pump, the delivery valve position, and the flow rate set point,based on the type of the defect.

According to a four hundred and thirty-sixth embodiment, in the methodsof the four hundred and thirty-fourth or four hundred and thirty-fifthembodiments, the dimensions comprise at least one of a diameter, aradius, a circumference, and an outer peripheral length.

According to a four hundred and thirty-seventh embodiment, the method ofthe four hundred and thirty-sixth embodiment further comprises measuringin real-time or near real-time at least one of a skinning pipe pressure,a delivery pressure, a return pressure, the speed of the pump, thedelivery valve position, the flow rate, the viscosity, the dimensions ofthe incoming unskinned articles, the skinning speed, or the pressurerelief system position.

According to a four hundred and thirty-eighth embodiment, the presentdisclosure relates to a method of controlling a skinning system thatapplies a flowable mixture to an article. The method may includepushing, using an article feeding mechanism, the article into an innerspace of a skinning pipe, applying, using the skinning pipe, theflowable mixture received from a mixture delivery system to the articleas the article moves axially along the inner space of the skinning pipe,and measuring at least one of a flow rate of the flowable mixture, aviscosity of the flowable mixture, or dimensions of incoming unskinnedarticles. The method may also include determining, using a feed forwardcontroller, an adjustment to at least one of a delivery pressure setpoint, a return pressure set point, a speed of a pump, a delivery valveposition, a flow rate set point, a skinning speed, and a pressure reliefsystem position, based on a variation in at least one of the measuredflow rate, viscosity, or dimensions of the incoming unskinned articles.

According to a four hundred and thirty-ninth embodiment, the method ofthe four hundred and thirty-eighth embodiment further comprisesmonitoring presence of a defect on a skinned article coated with theflowable mixture.

According to a four hundred and fortieth embodiment, in the method ofthe four hundred and thirty-ninth embodiment, monitoring the presence ofthe defect comprises detecting a type of the defect.

According to a four hundred and forty-first embodiment, the methods ofany of the four hundred and thirty-ninth or four hundred and fortiethembodiments further comprise determining, using a feedback controller,at least one of a skinning pipe pressure set point, the deliverypressure set point, the return pressure set point, the speed of thepump, the delivery valve position, and the flow rate set point, based ona result of monitoring the presence of the defect on the skinnedarticle.

According to a four hundred and forty-second embodiment, the method ofthe four hundred and forty-first embodiment further comprisestransmitting a control signal to at least one of the mixture deliverysystem and the skinning system based on an output from at least one ofthe feed forward controller and the feedback controller.

According to a four hundred and forty-third embodiment, in the methodsof any of the four hundred and thirty-eighth, four hundred andthirty-ninth, or four hundred and fortieth embodiments, the dimensionscomprise at least one of a diameter, a radius, a circumference, and anouter peripheral length.

According to a four hundred and forty-fourth embodiment, the method ofthe four hundred and forty-third embodiment further comprises measuringin real-time or near real-time at least one of a skinning pipe pressure,a delivery pressure, a return pressure, the speed of the pump, thedelivery valve position, the flow rate, the viscosity, the dimensions ofthe incoming unskinned articles, the skinning speed, or the pressurerelief system position.

According to a four hundred and forty-fifth embodiment, the methods ofany of the four hundred and thirty-eighth, four hundred andthirty-ninth, or four hundred and fortieth embodiments further comprisedetermining the speed of the pump based on a measured return pressure ordelivery pressure.

According to a four hundred and forty-sixth embodiment, the method ofthe four hundred and forty-fifth embodiment further comprisesdetermining at least one of the return pressure set point and thedelivery pressure set point based on a measured skinning pipe pressureand determining the speed of the pump also based on at least one of thereturn pressure set point and the delivery pressure set point.

According to a four hundred and forty-seventh embodiment, in the methodof the four hundred and forty-sixth embodiment, monitoring the presenceof the defect comprises detecting a type of the defect, and the methodfurther comprises determining the skinning pipe pressure set point basedon the type of defect and determining at least one of the returnpressure set point and the delivery pressure set point also based onskinning pipe pressure set point.

According to a four hundred and forty-eighth embodiment, the method ofthe four hundred and forty-first embodiment further comprisesdetermining at least one of the speed of the pump and the delivery valveposition based on a measured skinning pipe pressure.

According to a four hundred and forty-ninth embodiment, in the method ofthe four hundred and forty-eighth embodiment, monitoring the presence ofthe defect comprises detecting a type of the defect, and the methodfurther comprises determining the skinning pipe pressure set point basedon the type of defect and determining at least one of the speed of thepump and the delivery valve position also based on the skinning pipepressure set point.

According to a four hundred and fiftieth embodiment, the method of thefour hundred and forty-first embodiment further comprises determiningthe speed of the pump based on a measured flow rate of the flowablemixture in the mixture delivery system.

According to a four hundred and fifty-first embodiment, the method ofthe four hundred and fiftieth embodiment further comprises the method ofthe four hundred and forty-third embodiment further comprises anddetermining the speed of the pump also based on the flow rate set point.

According to a four hundred and fifty-second embodiment, in the methodof the four hundred and fifty-first embodiment, monitoring the presenceof the defect comprises detecting a type of the defect, and the methodfurther comprises determining the skinning pipe pressure set point basedon the type of defect and determining the flow rate set point also basedon the skinning pipe pressure set point.

According to a four hundred and fifty-third embodiment, the methods ofany of the four hundred and thirty-eighth, four hundred andthirty-ninth, or four hundred and fortieth embodiments further comprisedetermining an adjustment to at least one of the return pressure setpoint and the delivery pressure set point based on the variationrelating to at least one of the measured viscosity and measured flowrate.

According to a four hundred and fifty-fourth embodiment, the methods ofany of the four hundred and thirty-eighth, four hundred andthirty-ninth, or four hundred and fortieth embodiments further comprisedetermining an adjustment to at least one of the speed of the pump andthe delivery valve position based on the variation relating to at leastone of the measured viscosity and the measured flow rate.

According to a four hundred and fifty-fifth embodiment, the methods ofany of the four hundred and thirty-eighth, four hundred andthirty-ninth, or four hundred and fortieth embodiments further comprisedetermining an adjustment to the flow rate set point based on thevariation relating to at least one of the measured viscosity and themeasured flow rate.

According to a four hundred and fifty-sixth embodiment, the method ofthe four hundred and forty-third embodiment further comprisesdetermining an adjustment to the skinning speed based on the variationrelating to the dimensions of incoming unskinned articles measured inthe skinning system.

According to a four hundred and fifty-seventh embodiment, the method ofthe four hundred and forty-third embodiment further comprisesdetermining an adjustment to the pressure relief system position basedon the variation relating to the dimensions of incoming unskinnedarticles measured in the skinning system.

According to a four hundred and fifty-eighth embodiment, the method ofthe four hundred and forty-first embodiment further comprisesdetermining the skinning speed based on a measured skinning pipepressure.

According to a four hundred and fifty-ninth embodiment, the method ofthe four hundred and forty-first embodiment further comprisesdetermining the pressure relief system position based on a measuredskinning pipe pressure.

According to a four hundred and sixtieth embodiment, the method of thefour hundred and forty-third embodiment further comprises switchingbetween a first skinning pipe pressure control scheme and a secondskinning pipe control scheme, based on the dimensions of incomingunskinned articles measured in the skinning system.

According to a four hundred and sixty-first embodiment, the presentdisclosure relates to a method of adjusting a pressure of a flowablemixture adjacent a skinning pipe configured to apply the flowablemixture to an article. The method may include actuating a ring disposedaround an outer surface of the skinning pipe to adjust a space adjacentthe skinning pipe that is available for the flowable mixture to flow.

The construction and arrangements of the systems and methods forskinning articles, as shown in the various examples, are illustrativeonly. Although only a few examples have been described in detail in thisdisclosure, many modifications are possible (e.g., variations in sizes,dimensions, structures, shapes and proportions of the various elements,values of parameters, mounting arrangements, use of materials, colors,orientations, etc.) without materially departing from the novelteachings and advantages of the subject matter described herein. Someelements shown as integrally formed may be constructed of multiple partsor elements, the position of elements may be reversed or otherwisevaried, and the nature or number of discrete elements or positions maybe altered or varied. For illustrative purposes, some figures may notshow all elements included in a system or method. Such system or methodmay nevertheless include any other elements shown in any other figuresor otherwise disclosed in the present disclosure. The order or sequenceof any process, logical algorithm, or method may be varied orre-sequenced according to alternative examples. Other substitutions,modifications, changes, combinations, and omissions may also be made inthe design, operating conditions and arrangement of the various exampleswithout departing from the scope of the present disclosure. Any one ormore features of any example may be used in any combination with any oneor more other features of one or more other examples. It is intendedthat the specification and examples be considered as exemplary only,with a true scope being indicated by the following claims and theirequivalents.

1-36. (canceled)
 37. A skinning system for applying a flowable mixtureto an article, comprising: a skinning pipe configured to receive thearticle and apply the flowable mixture to the article as the articlemoves axially through the skinning pipe; a manifold including aplurality of grooves configured to deliver the flowable mixture to theskinning pipe; and a skinning control system comprising: a feed forwardcontroller configured to determine an adjustment to at least one of adelivery pressure set point, a return pressure set point, a speed of apump, a delivery valve position, a flow rate set point, a skinningspeed, or a pressure relief system position, based on a variationrelating to at least one of a flow rate of the flowable mixture, aviscosity of the flowable mixture, or dimensions of incoming unskinnedarticles.
 38. The skinning system of claim 37, wherein the dimensionscomprise at least one of a diameter, a radius, a circumference, or anouter peripheral length.
 39. The skinning system of claim 38, furthercomprising: at least one feedback controller configured to determine atleast one of a skinning pipe pressure set point, the delivery pressureset point, the return pressure set point, the speed of the pump, thedelivery valve position, or the flow rate set point, based on a resultof monitoring presence of a defect on a skinned article coated with theflowable mixture.
 40. The skinning system of claim 39, furthercomprising: a communication unit configured to transmit a control signalto at least one of a mixture delivery system or the skinning systembased on an output from at least one of the feed forward controller orthe feedback controller.
 41. The skinning system of claim 40, whereinthe communication unit is configured to receive real-time or nearreal-time measurements of at least one of a skinning pipe pressure, adelivery pressure, a return pressure, the speed of the pump, thedelivery valve position, the flow rate, the viscosity, the dimensions ofthe incoming unskinned articles, the skinning speed, or the pressurerelief system position.
 42. The skinning system of claim 39, wherein theat least one feedback controller comprises: a first feedback controllerconfigured to determine the speed of the pump based on a measured returnpressure or delivery pressure.
 43. The skinning system of claim 42,wherein the at least one feedback controller comprises: a secondfeedback controller configured to determine at least one of the returnpressure set point or the delivery pressure set point based on ameasured skinning pipe pressure, wherein the first feedback controlleris configured to determine the speed of the pump also based on at leastone of the return pressure set point or the delivery pressure set point.44. The skinning system of claim 43, wherein monitoring the presence ofthe defect comprises detecting a type of the defect, and wherein the atleast one feedback controller comprises: a third feedback controllerconfigured to determine the skinning pipe pressure set point based onthe type of defect, wherein the second feedback controller is configuredto determine at least one of the return pressure set point or thedelivery pressure set point also based on skinning pipe pressure setpoint.
 45. The skinning system of claim 39, wherein the at least onefeedback controller comprises: a first feedback controller configured todetermine at least one of the speed of the pump or the delivery valveposition based on a measured skinning pipe pressure.
 46. The skinningsystem of claim 45, wherein monitoring the presence of the defectcomprises detecting a type of the defect, and wherein the at least onefeedback controller comprises: a second feedback controller configuredto determine the skinning pipe pressure set point based on the type ofdefect, wherein the first feedback controller configured to determine atleast one of the speed of the pump or the delivery valve position alsobased on the skinning pipe pressure set point.
 47. The skinning systemof claim 39, wherein the at least one feedback controller comprises: afirst feedback controller configured to determine the speed of the pumpbased on a measured flow rate of the flowable mixture in the mixturedelivery system.
 48. The skinning system of claim 47, wherein the atleast one feedback controller comprises: a second feedback controllerconfigured to determine the flow rate set point based on a skinning pipepressure measured in the skinning system, wherein the first feedbackcontroller is configured to determine the speed of the pump also basedon the flow rate set point.
 49. The skinning system of claim 48, whereinmonitoring the presence of the defect comprises detecting a type of thedefect, and wherein the at least one feedback controller comprises: athird feedback controller configured to determine the skinning pipepressure set point based on the type of defect, wherein the secondfeedback controller is configured to determine the flow rate set pointalso based on the skinning pipe pressure set point.
 50. The skinningsystem of claim 37, wherein the feed forward controller comprises: asecond feed forward controller configured to determine an adjustment toat least one of the return pressure set point or the delivery pressureset point based on the variation relating to at least one of themeasured viscosity or measured flow rate.
 51. The skinning system ofclaim 37, wherein the feed forward controller comprises: a second feedforward controller configured to determine an adjustment to at least oneof the speed of the pump or the delivery valve position based on thevariation relating to at least one of the measured viscosity or themeasured flow rate.
 52. The skinning system of claim 37, wherein thefeed forward controller comprises: a second feed forward controllerconfigured to determine an adjustment to the flow rate set point basedon the variation relating to at least one of the measured viscosity orthe measured flow rate.
 53. The skinning system of claim 38, wherein thefeed forward controller comprises: a second feed forward controllerconfigured to determine an adjustment to the skinning speed based on thevariation relating to the dimensions of incoming unskinned articlesmeasured in the skinning system.
 54. The skinning system of claim 38,wherein the feed forward controller comprises: a second feed forwardcontroller configured to determine an adjustment to the pressure reliefsystem position based on the variation relating to the dimensions ofincoming unskinned articles measured in the skinning system.
 55. Amethod of controlling a skinning process that applies a flowable mixtureto an article, comprising: measuring, using at least one laser device, avariation relating to a dimension of one or more incoming unskinnedarticles; determining, using a feed forward controller, an adjustment toa skinning speed or a pressure relief system position based on themeasured variation; and transmitting a control signal to a skinningsystem to adjust at least one of the skinning speed or the pressurerelief system position, based on an output from the feed forwardcontroller.
 56. The method of claim 55, wherein the dimension comprisesat least one of a diameter, a radius, a circumference, or an outerperipheral length.